Friday, June 15, 2012

Leveraged Bullpen Use

ESPN decided to really go after the outdated save rule and it's effects on bullpen management, or more appropriately mismanagement, today (see CapleSchoenfield, or Cameron) so I thought I'd join the bandwagon and look at how efficiently relievers are being used around the league.

I'm going to compare how the runs each teams' bullpen gives up once the leverage of the situation is taken into account. To do this I'll be using Fangraph's Leverage Index, specifically gmLI, a pitcher's average Leverage Index when he enters the game. I'll be using a metric called Leveraged ERA (L-ERA) calculated for each team's bullpen. I calculate L-ERA by first weighting each pitcher's earned runs by their respective Leverage Index (ER*gmLI). This is then summed for each pitcher in a teams bullpen and divided by the total number of innings pitched. This value is the unnormalized L-ERA. This value needs to be normalized by the team's Leverage Index in order to account for the fact that different teams face different leverage situations. The Twins bullpen has a particularly low Leverage Index because they are usually so far out of the game by the time the bullpen needs to pitch. The team LI is calculated by calculating a weighted average of the players' Leverage Indexes by the amount of innings pitched. The unnormalized L-ERA is divided by the team LI to get the final L-ERA value.

L-ERA weights the runs the bullpen has given up according to the leverage of the situation. Runs given up in a close game are much more important than those given up in a blowout. The difference between a team's ERA and L-ERA can determine how effective the bullpen has been and how appropriately it has been deployed. Along this vein it is important to note that the L-ERA number alone cannot distinguish between clutchness and management, although they are definitely related. We'll look through some of the extreme cases to try and determine whether the difference was caused by extreme performances or by managers deploying their less effective relievers in more important situations. Table 1 shows the ERA, L-ERA, and the difference between the two (Δ) for each team's bullpen. A higher Δ value indicates the bullpen has been extremely effective, having the best performances in the highest leverage situations. Similarly a low Δ value indicates that a bullpen has performed worse (or used worse) in more important situations.

Table 1: Bullpen ERA and L-ERA. Δ = ERA - L-ERA

We see that the bullpens of the Giants and Rangers have performed the best in higher leverage situations. Since Brian Wilson went down Sergio Romo and Santiago Casilla have performed incredibly well and have been used in high leverage situations. The Giants bullpen could probably be even better as Javier Lopez and his 3.29 ERA has thrown 13.2 innings in the highest leverage situations on the team. The Rangers seem to be benefiting much more from clutch performance than solid bullpen management. Robbie Ross has the lowest ERA and has thrown the most innings on the team, but he ranks only 4th among relievers in terms of leverage situations. Just like the Giants, the Rangers have also been giving their highest leverage innings to one of their weaker performers, that being Mike Adams and his 3.32 ERA.

At the other end of the spectrum we have the Red Sox and Astros. The Red Sox have been relying heavily on Vincente Padilla and Alfred Aceves to anchor their bullpen and the results haven't been great so far. These two players have the highest leverage situations on the team and both have ERAs over 4.50. Meanwhile Scott Atchison and Matt Albers have thrown 61 innings with an ERA under 2, but have been used almost exclusively in below average leverage situations. As for the Astros, their best reliever Brett Myers has been used in the highest leverage situations, but no where near often enough. Myers is only 4th in the bullpen in terms of innings pitched and he can easily pitch more given his past as a starter. Maybe the Astros are keeping him rested for a trade? So instead of letting Myers pitch the important innings, they've been going to Fernando Rodriguez and his 4.56 ERA.

Much has been made about the Phillies and their use, or lack thereof, of Papelbon. It might be a little surprising then to see the Phillies in the upper third of teams in terms of differential. Similar to Houston, the problem hasn't been Papelbon's performance, it's been his under use. Papelbon and Antonio Bastardo have been two of the best relievers on the team and have been used in high leverage situations. Unfortunately so has Chad Qualls who leads the team in innings but has a 4.56 ERA.

Sometimes a manager doesn't know exactly how a pitcher will do until he takes him for a bit of a test run. This often follows a call-up from the minors and is then frequently followed by a subsequent option back to AAA. To try and get a better reading on mainstays in the bullpen, I repeated this analysis using only pitchers that have pitched at least 10 IP for their respective team. The results are shown in Table 2. Not surprisingly the overall ERA drops from 3.65 when all pitchers are considered to 3.36 when only the 10 IP pitchers are included. Better quality pitchers have a better chance of sticking around. This also eliminates some of the more fluky incidents such as Darnell McDonald giving up 3 runs in a very important 17th inning.

Table 2: Bullpen ERA and L-ERA, Minimum 10 IP/player. Δ = ERA - L-ERA

Unfortunately for the Red Sox eliminating McDonald doesn't eliminate Aceves' early season blowups. We do see some shuffle in the chart though. The Angels jump way up the list by realizing that Bobby Cassevah and Kevin Jepsen belong in the minors. The Astros also look better as they the 10 IP minimum removes 4 pitchers from their bullpen, although they still need to see Myers more.

These results should be taken with a bit of a grain of salt. I used each player's average gmLI to determine the L-ERA. It would be more informative to weight each run by the exact leverage index of the situation it was given up with. Similarly, although the normalization tries to make it so that each team is compared to itself, since we are comparing the differences between teams it isn't entirely fair to use different normalization values for different teams. It isn't entirely a pitcher's control what the leverage situation is when he enters, he can only affect his own performance. A batter entering needing to get one out to close an inning and getting a strikeout has performed his job equally well whether the bases were empty or loaded. However, to lower the L-ERA with the highest probability, a manager can make the active decision to put his best reliever in when the stakes are raised. It is also important to note that the average bullpen has only thrown 186.2 innings so far, the results will become much more meaningful once the sample size can increase at least beyond an expected starter's workload.

Thursday, June 14, 2012

Birds fly, Sun Rises, Pitcher throws perfect game

Before crawling into bed last night I pulled up ESPN on my phone. Upon seeing that Cain had thrown a perfect game (introduced by the inexcusably bad title "Perfectly Able") my initial thought was "Wow, good for him". I didn't have a second thought, I put my phone down and went to sleep.

No-hitters and perfect games are supposed to be rare unbelievable performances, games that you'll always remember exactly where you watched them. Given all the no-hitters lately it's getting hard to keep track. Cain's perfect game last night was the third no-hitter in two weeks. As baseball fans we've been spoiled by all the spectacular pitching performances lately. Before we've come down from the emotional high of one game, we're treated with another. Cain may have pitched the greatest game of all time, but the news just seems so ordinary.

We've called each of the last three seasons 'The Year of the Pitcher" but that might not be doing it justice. Pitchers' ERA has dropped by 0.58 runs just since 2006. But massive TV contracts have created tiers of have and have-not teams, and those have-not teams are trotting out lineups each game that would embarrass most AAA teams. Of the 5 no-hitters this season, three have been thrown against Seattle, Minnesota, and Houston, teams that score collectively 0.22 runs less per game than league average. This along with the end of the steroid era, better training, and better available information has made the frequency of historic pitching performances sky rocket.

1We've seen 5 no-hitters so far this season and it's only halfway through June. Previously, the most no-hitters through the first 64 games of a season was 3. Even if we ignore the combined no-hitter this season still breaks the record. Even having 3 no-hitters at this point has only happened 5 times previously and one of those occurrences was only two seasons ago in 2010. There have only been 3 seasons that have even had more no-hitters total. June isn't exactly known for it's no-hitters either, only the 1990 season had at least 3 no-hitters in it. Although it's not like any month is really known for having this many no-hitters. Outside of the Junes of 1990 and 2012, no other month since 1918 has seen 3 no-hitters in a single season. This shouldn't be that surprising, the 14 no-hitters we've had since 2010 (counting Halladay's playoff one) can be beaten only by the 15 from '67-'69, '68-'70, '88-'91, and '90-'922, and this season isn't even over yet. Plus the combined three perfect games from those two four-year stretches don't match the four we've already seen since 2010.

It isn't just the once elusive no-hitter that seems to be popping up every week though. There have been 66 one-hitters thrown since 2009 are matched only by the four year stretch from '85-'88, and as I continually mention, this current stretch is only counting 64 games from the fourth season. League-wide, the number of such high quality games has never been this good.

Let's not forget Matt Cain though. At this point already he's already having a historically great season. Only 68 other pitchers have thrown at least two one-or-less hitters in an entire season, but few have done it as well as Cain. Of those 68 players's seasons, only 23 had at least 1 no-hitter, and like Cain only Jim Bunning was able to do it without giving up a walk in either of those two starts. Of the 23 players with at least one no-hitter, only Koufax and Nolan Ryan were able to do it with more strikeouts. If we consider that Cain has also thrown a two-hitter, we can count only 6 other players that have thrown three two-hitters or less at this point in the season and Cain has struck out more, walked less, and given up less hits in those three games than any of them.

It truly says a lot of this era then that if the season were to end today that Cain might not even win the Cy Young. R.A. Dickey is just trailing Cain in ERA 2.20-2.18 and has 6 less strikeouts (Cain and Dickey are second and fourth respectively), but Dickey is also working on a 32.3 inning scoreless streak that he'll look to continue against the Orioles next week. Let's not forget about that kid up in Washington either.

There has been a lot to appreciate about pitchers lately, maybe a little too much. I don't want to go back to steroid era run levels but since 2000 we've lost over 1000 home runs per season. Watching a no-hitter or perfect game is always entertaining, and I loved seeing the recap and watching the full ninth inning of last night's game this morning, but at some point you want to see the pressure packed situations of seeing men on base. Plus, who doesn't love the long ball?

1All data presented from this point on is for seasons 1918-2012
2Note that these eras overlap

Tuesday, June 12, 2012

Hurts so Vlad

With the Jays' release of Vladimir Guerrero today his career has mercifully come to an end. I hope. I originally predicted that Vlad wouldn't play a single game for the Jays, but as much as I wish that Vlad would go gently into the good night my gut tells me that there's at least one more failed minor league stint in his future. Guerrero still thinks he can play (and had a few choice words for Jays' management) and there's never a shortage of desperate GMs looking to give a once major power threat a few at bats. For today though we're going to play out the fantasy and act as if this is it for Vlad. That means in five years time voters will need an answer on whether or not he's Hall worthy. Let's save some time and get an answer now.

Let's get the shiny numbers out of the way first. Vlad hit .318/.379/.553 for his career with 449 HR. He finished with 2590 hits, 972 of them for extra bases. He was no slouch on the base paths, having stolen 181 bases, although perhaps not the most efficient base thief with only a 65.8% success rate. He won the MVP award in 2004 and finished in the top 4 in voting 3 other times. He won 8 Silver Slugger awards and was a 9 time All-Star. He finished with 55.2 rWAR and 60.0 bWAR.

For such a great player Vlad was remarkably consistent. From 1998-2007 there were few players in the league who could be as dangerous as the bat as he was. Vlad had a knack for putting any ball into play, no matter how far off the plate the pitch may have been (see video). Although for such a free swinger he still took his share of walks. His 8.1% walk percentage compares well to recent outfield Hall honourees, Andre Dawson (5.5%), Jim Rice (7.4%), Tony Gwynn (7.7%), Dave Winfield (9.8%), and Kirby Puckett (5.7%).

It's hard to talk about Guerrero's career peak since his peak lasted for about 10 seasons. From 98-07 Vlad batted above .300 in every season, had a minimum of 3 WAR in every season, and had 8 years with 30+ HRs. It's interesting to see how his 10 year stretch compares to other outfielders. The following table shows the best 10 year stretch and associated rWAR from all the HoF outfielders elected since 1970 plus a few other potential ones thrown in.

Vlad is in good company. I don't think anyone expected him to be close to the likes of players such as Mays or Bonds but he fits in well with a second tier of outfielders who are still HoF worthy. Just to compare Vlad closer to some of the more recently elected outfielders (excluding Rickey who I consider to easily fall into the top tier of HoF outfielders), the following graph shows that until his late career dropoff, Vlad was outpacing all of them. We see almost the exact same thing in the second graph when comparing him to more recent outfielders.

Through the prime years of his career Vlad beats out all his comparables. His career ISO mark of .235  ranks 49th all-time (min. 5000 PA) and his wOBA of .389 beats out outfielders such as Rickey Henderson and Junior Griffey. He's also one of only five players on the above list who has at least twice joined the 30-30 club.

Guerrero's bat and increasingly poor outfield defense eventually did him in, probably a few years earlier than most baseball fans would have hoped for. Throughout his career though there were few players more fun to watch hit and coupled with the evidence presented here I'd definitely consider him a Hall of Fame player. The image of him standing in the box barehanded and knowing that a pitch anywhere could be put into the stands will stand for many years to come. I think it should also be noted, that although there is obviously no way to prove innocence, Guerrero played through the steroid era and was never implicated in any performance enhancing drug scandal. There was also nothing like that chill that ran through your spine as Vlad was about to unload his cannon on a throw to the plate.

I'm wondering which team would be most appropriate to put Vlad into the Hall with, but I can't think of a better image for his plaque than him with a helmet so dirty the logo has been completely scratched off. Vlad parts of 8 seasons in Montreal compiling 32.9 WAR while his 6 years on the (Insert name here) Angels collected him 20.9 WAR. However his MVP season came with the Angels as well as five of his six trips to the post season. I always like to see Canadian teams pile up more plaques in the Hall but I couldn't complain with him going in as an Angel. I'm sure Vlad's input will be important here too. In the end he should eventually get in, although he'll probably have to wait a few years as punishment for the era and because of a backlog of other players facing the similar crime. Hopefully his 5 year wait period will start counting today.