Jon Heyman of Sports Illustrated had an interesting tweet this morning. He claimed that Joel Hanrahan of the Pirates was the best reliever in baseball right now. I’m a Braves fan, and my feed has been blowing up all morning with people degrading Heyman and shouting the name “Jonny Venters” from the highest mountains. I thought it would be good to look at who the best relievers in baseball have been this season, and if Heyman’s Hanrahan claim has any weight at all.
Before I get into the analysis, I’d like to explain a few stats I’ll be using in this piece. ERA is…well, ERA. (Earned runs * 9) / innings pitched. That determines how many earned runs a pitcher allows every nine innings. That’s an easy one. Next, there’s FIP. The formula for FIP is (Homers * 13 + walks * 3 – strikeouts *2) / innings pitched, and then adding 3.20 to the final number. This gives you a player’s expected ERA based on the factors that the player can control: home runs, walks, and strikeouts. It tries to take defense out of the equation, because a good defense and a bad defense can make a world of difference when looking at a pitcher. Finally, there’s xFIP, which adds in a neutral fly ball ratio to even out ballpark factors. For example, a pitcher playing in Coors Field will generally allow more home runs than a pitcher playing in Citi Field. It also helps out pitchers who get an absurd amount of ground balls, as FIP doesn’t take groundball ratio into account. With all that said, let’s get to some analysis!
First, let’s take a look at Hanrahan, closing out games for the surprising Pittsburgh Pirates. Quite frankly, he’s been damn good. He’s got a 1.24 ERA, and the advanced metrics back things up, as his FIP is 2.24 and his xFIP is 2.72. Those are damn good numbers. When you factor in his 22 saves (second in the majors behind Brian Wilson and Huston Street), and you can see why Heyman made his claim. The thing about Hanrahan is that he’s not striking out a ton of batters, only 7.68 batters per nine innings, in comparison to 12.92 batters per nine last season with the Pirates. But with the decrase in strikeouts has a come a decrease in walk rate, which has fallen from 3.36 last season to 1.98 last season. His strikeout to walk ratio has remained constant with both drops, going from 3.85 last year to 3.88 this season. While that’s a good mark, it’s outside of the top fifteen in the majors.
A common name thrown out by many fans as the “real” best reliever in baseball is Jonny Venters of the Braves. He’s been downright dominant this year, with a 0.56 ERA, 2.02 FIP, and 2.25 xFIP. He’s put up those numbers with quantity too, as the 48 1/3 innings that Venters has thrown are a league high for pitchers who haven’t started a game. There’s also the point of his obscene 80.4% groundball rate put up by Venters, the best in baseball by far. But Venters has his flaws as well. He’s striking out 9.50 batters per nine innings and walking 2.98 per nine, giving him a 3.19 K:BB ratio that is lower than Hanrahan’s and isn’t in the top 30 of the majors. He’s also been extremely lucky, with a .214 batting average on balls in play (BABIP) that is in a cluster among the lowest in the league. Venters has also stranded 90.7% of the runners he’s put on base, another extremely high mark (though there are higher). But you know what? When you look at wins above replacement (WAR) for relievers, Venters’ mark of 1.5 is the best in baseball. Statistically, he HAS been the best reliever in baseball this year. While he’s been great, a lot of that has been due to the sheer volume of innings he’s thrown.
Another contender for the “best reliever” label plays in the Bronx, but is probably not the name you’re thinking of. David Robertson of the Yankees has been excellent. He has a 1.19 ERA, 1.76 FIP, and 2.52 xFIP. and is striking out 14.24 batters per nine, the third best mark in baseball. His walk rate is high at 5.93 per nine, but he hasn’t allowed a homer all season. Robertson has been both lucky and unlucky, with an unlucky .338 BABIP screwing him over, and a 88.1% strand rate proving to be a little lucky for his numbers. His teammate, Mariano Rivera, has been great, but not as great as he has been in the past. A declining strikeout rate (7.06) and a still excellent walk rate (1.23) give him a 5.75 K:BB ratio, which is still one of the best in the majors. He’s got a 1.84 ERA, 2.23 FIP, and a 3.19 xFIP. As I said….he’s been damn good, but not elite like he had been in years past.
Another candidate is Sergio Romo of the Giants. He’s got a 13.50 strikeout rate, which is one of the best in the league, and a 1.50 walk rate, also one of the best in the league. Put it in a blender, and you get a 9.00 strikeout to walk ratio that is near the top of the league. When all is said and done, Romo has the best FIP in baseball at 1.53, and the best xFIP at 1.64, though his 2.25 ERA is a little high in comparison to some of the other pitchers on this list. The only thing holding Romo back from being truly elite is his home run rate, which is a little high at 0.75 per nine innings. Romo has been much better than his more publicized teammate Brian Wilson, and should really be getting more attention.
What about Mike Adams of the Padres? He has a great rate stats, with a 9.72 strikeout rate and 1.08 walk rate. A 1.35 ERA, 1.93 FIP, and 2.42 xFIP show just how good he’s been. Maybe Vinnie Pestano of the Indians? He’s striking out 12.21 per nine innings, walking 3.21 per nine innings, and has a fancy 1.29 ERA for the surprising Tribe. Any other candidates? Kyle Farnsworth and Matt Capps are tied for the best K:BB in the league at 10.00, but neither is striking out more than six batters per nine innings, and only have ratios that high due to not walking any batters, which has not been typical for either of their careers. Both pitchers are allowing a decent amount of hits, and Capps has been sunk by allowing a few home runs. Farnsworth has been a great comeback story, while Capps has been more of a “how in the hell is THIS guy doing this?” story.
The jist of what I’m getting at here is that Heyman wasn’t totally offbase by calling Hanrahan the best reliever in the game. He’s having an excellent season for a shockingly good Pirates team, and he’s a good story too. But there are *a lot* of great relievers in the game this season so far. Venters has been the best in terms of sheer quantity of innings, Robertson has been a strikeout phenom for a team battling for supremacy in the always tough AL East, and Romo has had some of the most amazing rate stats in the league this season. There are a few directions you can go when determining who the best really is. I don’t think there’s really a right answer, but you shouldn’t get all up in arms just because you disagree with someone. Hanrahan is a fine choice, just not maybe the best choice.
