This is the American League relievers complement to the recent Fanpost that summarized the results of applying my Fielding and Ballpark Independent Outcomes system to 2013's American League starting pitchers.
The 39 lefthanded pitchers who faced at least 100 batters as an American Leaguer while averaging less than 10 batters faced per game, plus the 62 righthanded pitchers who faced at least 150 batters as an American Leaguer while averaging less than 10 batters faced per game. These pitchers will be considered "relievers" for the sake of this post.
All plate appearances against said pitcher while they were an American Leaguer, save for foulouts, bunts, and those in which a pitcher batted.
The methodology is explained in more detail in the prior starters' publication. The outcome of each plate appearance versus the pitcher was sorted into one of the 12 general event categories shown in the table below based on the web-accessible MLBAM Gameday data.
The pitcher is charged with the corresponding number of runs listed in the table for each such event they allowed, and that sum is ultimately divided by the total number of plate appearances against the pitcher to arrive at a single value that quantifies what a plate appearance versus the pitcher was worth in terms of runs, on average (the more negative that value, the better the pitcher performed). The average and standard deviation (SD) are computed for that sample of 101 values and the 101 pitchers are then each assigned a Performance Score based on how many SD they were better or worse versus the league's average for a reliever. A 50 score designates league-average performance (pitcher has topped or equaled 50% of peers), a 60 designates 1 SD better than league-average (topped or equaled 83% of peers), a 70 designates 2 SD better than league-average (topped or equaled 97% of peers), a 40 designates 1 SD worse than league-average (topped or equaled 17% of peers), a 30 designates 2 SD worse than league-average (topped or equaled 3% of peers), and so on with 1 SD amounting to 10 points. Besides that all-encompassing score, three other subscores are computed on the same 20-to-80 scale to assess how each pitcher performed with respect to control only (walks plus hit batsmen), strikeouts only, and batted balls only. Likewise, an Age Score was computed to quantify how young the pitcher was relative to the sample of 101 pitchers. The Performance Score, Control Subscore, Strikeout Score, and Batted Ball Subscore were also calculated looking only at lefthanded batters (LHB) and only at righthanded batters (RHB).
In the tables that follow, values that bettered the league average for that quantity by at least 1 SD are highlighted in green text whereas those that trailed it by at least 1 SD are in red text. Asterisks indicate lefthanded throwers.
Houston Astros: Scores and Event Frequencies
Recent waiver claim Downs topped all 7 of the qualifiers who had pitched for the 2013 Astros. Downs and Veras graded out rather similarly in subscores with batted ball outcomes being their particular forte. The other 6 qualifiers rated below league-average in Performance Score with Clemens, Cisnero, and Blackley each finishing in the Bottom 10. Further insight into each pitcher's relative strengths and weaknesses can be gleaned from their event frequencies below; note that the BB+HBP% and K% columns utilize the total number of plate appearances as the denominator while the remainder use the total number of batted balls instead.
Houston Astros: Batter-Handedness Splits
Downs' and Veras' relatively high overall rankings were each the product of very good outcomes versus same-handed bats (11th best versus LHB and 6th best versus RHB, respectively) and average ones versus opposite-handed bats. Fields graded out very well versus samehanded bats and very poorly opposite-handed ones (8th best versus RHB and 98th best versus LHB out of the 101 relievers). Lefty Blackley was particularly bad versus RHB (99th out of 101).
Houston Astros: Scores of Non-Qualifiers
Zeid, Lo, Cruz, and Chapman failed to reach the respective minimum batters faced threshold, but here's how they would have rated had they done so and continued to perform similarly on these measures.
Though the four remain rather young by American League relief standards, all of their Performance Scores and subscores fell below the league average for relievers. At this stage of these players' development, the numbers here suggest that it may be a bit of gamble to open 2014 with any of them slotted higher than the 5th best relief option.
American League: Top 20 Performance Scores
Uehara earned a 10-point higher Performance Score than top-starter-per-this-same-system and Cy Young winner Max Scherzer did, further emphasizing just how excellent Cy Young 7th-place-finisher Uehara's pitching campaign was. The number 2 spot in the rankings was held by Holland, the only other reliever to garner a Cy Young vote. Raise your hand if you expected Logan to place 3rd or higher on this list – more on him later.
American League: Potential New 2014 Houston Astros
Given that the bullpen figures to be an area of particular emphasis in constructing the 2014 Astros, let's take a look at how the class of possible additions to the roster from 2013 American League clubs rated per this system.
That San Antonio native Logan grades out to be very tough on lefties while also holding his own versus righties casts him as a good free agent fit for a club like the 2014 Astros where it would stand to be particularly difficult to shield lefty relievers from RHB. Veras' nearly average Control Subscore marks demonstrate a clear improvement versus his past results, and that he rates so well in Batted Ball Subscore versus LHB and versus RHB and that he seems open to rejoining the Astros makes him all the more obvious of a choice for a return gig in the closer's role.
While not a free agent, Chavez would stand to be acquirable in so much as he is 30 with a journeyman's pedigree (late-round draft pick who was traded four times prior to being claimed off waivers by the Athletics), only this past season beat the 4.00 season ERA barrier for the first time as a big leaguer (barely so), and seems to slot well down on his club's relief depth chart (did not pitch during their 5-game divisional series loss). Among what Chavez had going for him in 2013 was that he was among the most difficult relievers to pull an outfield flyball against (only 1.5% of his batted balls were of that particularly dangerous variety, versus the league average of 6.3%) - a characteristic that serves a pitcher well in MinuteMaid Park. He also features a quite diverse repertoire for a reliever, throwing 5 different pitches (4-seam fastball, 2-seam fastball, cutter, curve, change-up) at least 9% of the time per 2013 Pitch F/X data.
The factors that fueled the high Batted Ball Subscore ratings of one-time Astro Lindstrom, Smith, Thornton, and one-time Astro Albers would seem to logically push the foursome up the club’s offseason free agent wish list. But given that Lindstrom and Smith have already inked elsewhere and that the 37-year old Thornton would not figure to have Houston among his top two dozen potential 2014 employment destinations, Houston native Albers is the most likely of them to land in the 2014 bullpen; there is definite room for forward regression and/or outright improvement in the strikeout department and with such Albers would wind up looking rather similar on the 2014 version of this chart to how Lindstrom did in 2013.
In this exercise, I'm granting you the authority to sign either Jose Veras or Jesse Crain and sign/acquire two of Boone Logan, Matt Albers, and Jesse Chavez. Who are your preferred acquisition targets?