A few weeks back, the estimable Dan Epstein examined whether Yankees southpaw Aroldis Chapman was the greatest left-handed relief pitcher of all time. The name that kept popping up during that excellent article (which you should read) was Billy Wagner, the erstwhile Astros, Phillies, and Mets closer known for a blazing fastball and what is widely perceived to be a borderline Hall of Fame candidacy.
I’m here today to tell you that Wagner should be a lock for the Hall of Fame, as one of the greatest relief pitchers ever. With all due respect to Chapman, Wagner is inarguably the greatest southpaw reliever in baseball history.
How good was Wagner? Since 1871, there have been 376 relief pitchers to throw more than 500 innings. Unsurprisingly, the leader in fWAR among those 376 pitchers is one Mariano Rivera, who is probably irrefutably the best reliever of all time. Rivera is followed by Hall of Famers Goose Gossage, Rollie Fingers, Trevor Hoffman, and Lee Smith. In sixth place is one Billy Wagner, who has more fWAR than any left-handed relief pitcher in baseball history.
That probably undersells how good Wagner really was. Despite pitching in the Steroid Era, Wagner has the sixth-highest K/9 of any reliever in baseball history with more than 500 innings pitched. Wagner is fourth all-time among relievers in K%, at 33.2%, and fourth all time in K%-BB%, at 24.9%. Wagner is sixth all-time in FIP, fourth in ERA, and fifth all-time in win probability added. By ERA- and FIP-, Wagner is even more impressive; his 54 ERA- is third all time, behind just Rivera and Craig Kimbrel, and his 63 FIP- is fifth, right behind Rivera and well ahead of Hoffman. Fangraphs has Wagner’s fastball as the fourth-best of all time among relievers by pitch values, behind Kenley Jansen and ahead of Chapman.
The biggest knock on Wagner is generally the relatively small number of innings he threw in his career - “just” 903, compared to over 1200 for Rivera and Lee Smith. But Trevor Hoffman threw only 1089.1 innings in his career, with far inferior peripherals to Wagner across the board.
Moreover, the quality of those 900 innings Wagner threw was virtually peerless. Among all pitchers who have thrown at least 900 innings in their career - starters and relievers - since 1950, Wagner is first in strikeout rate. Literally no pitcher in baseball history with at least 900 innings has ever struck out a greater percentage of batters than Billy Wagner, Wagner’s K%-BB% is second all-time among pitchers with at least 900 innings, behind only Chris Sale, and better than Stephen Strasburg, Jacob deGrom, and Curt Schilling.
Let me put this another way. Only one pitcher in baseball history with at least 900 innings prevented runs better than Wagner, and that was Mariano Rivera. Only one pitcher with at least 900 innings had a lower WHIP than Wagner, again, it’s Rivera. No pitcher who threw at least 900 innings has given up fewer hits.
For comparison’s sake, Trevor Hoffman surrendered 846 hits in 1089 innings. Wagner, in 903 innings, surrendered just 601. Among all pitchers, starting and relief, with at least 900 innings, Wagner has the lowest batting average against in baseball history, ahead of Nolan Ryan and Sandy Koufax (Hoffman is eighth; Rivera is 11th). And despite tossing only 903 innings, Wagner saved 422 games, sixth-most all-time.
So yes, Wagner’s career was “only” 900 innings. They were, however, arguably the 900 most dominant innings ever thrown by any pitcher ever. Wagner’s peripherals are comparable to those of Josh Hader, widely considered among the best left-handed relief pitchers today. The difference is that Wagner put up Hader-like numbers for fifteen straight years.
It’s also worth noting that 900 innings is not as few as you might think. Let’s take a look at the three active closers most often mentioned as one day worthy of Hall of Fame consideration: Aroldis Chapman, Kenley Jansen, and Craig Kimbrel. Chapman, 31, debuted in 2010, has pitched in every year of this decade, and still has only 535.2 innings heading into his age 32 season; to match Wagner’s total, he’ll have to pitch for another eight years at his current rate. Kimbrel, also 31, is headed into his age-32 season with 553.1 innings, approximately the same pace as Chapman. Jansen, the oldest of the bunch at 32, is at 611 innings, and would have to pitch another five years to match Wagner. The problem is that all three saw their effectiveness slip to varying degrees this year. That’s a problem Wagner never really had.
So nine hundred innings doesn’t sound like much until you consider that no active reliever is a lock to get there. Thirty-four year old Andrew Miller, who served as a starter for much of his career, still has only 780 career innings to his name at the big league level. Mark Melancon, also 34, has pitched out of the bullpen for his entire career and hasn’t yet hit even 600 innings.
In that light, it’s hard to argue that Wagner isn’t deserving of enshrinement in the Hall of Fame. He is the greatest left-handed reliever of all time, simply because, whilst he pitched, he was the second-best per-inning pitcher on the planet. If Mariano Rivera hadn’t existed, Wagner would have been recognized as the greatest reliever of his era. Excepting Rivera, no reliever currently in the Hall of Fame - not Smith, not Hoffman, not Eckersley, not Gossage - was better than Wagner. For nine hundred innings, Billy Wagner was the best left-hander this game has ever seen.