I was inspired by sansho1 to look a little harder at EOF.

Unless your league counts holds, Eric O’Flaherty isn’t much good for fantasy purposes because he isn’t a closer: he has zero career saves. And his one entry in the record books — most most relief innings pitched in a season with an ERA under 1.00, set back in 2011 (0.98 ERA, 73 2/3 IP) — became a historical footnote when Fernando Rodney passed him this year (0.60 ERA, 74 2/3 IP). Like sansho noted, he’s got a 91-mile an hour fastball: decent but not great. He’s got a career 3.84 xFIP, which doesn’t seem great. But he has the second-best ERA- in baseball over the past four years. I’d call him the most underrated reliever in baseball.

Eric O’Flaherty was drafted by the Seattle Mariners out of Walla Walla High School in the sixth round of the 2003 draft by his local team, the Seattle Mariners. He didn’t strike many people out in Rookie or Low-A ball, but then he added strikeouts and improved his control as a 21-year old in 2006, breaking out in a major way as he moved from High-A to Double-A to Triple-A. He made the main club the next year, but struggled with his control, struggled some more when they sent him back to the minors, and then suffered a back injury.

Basically, as Mac wrote, “The Mariners rushed him, and wound up wasting three years of options and losing him.” After he’d struggled as a situational lefty, the club put him on waivers, and the Braves claimed him as the 23-year old lefty had a 5.91 ERA in 70 major league innings. As Jay Yenich wrote at USS Mariner earlier this year:

[T]he first “hey, wait a second…” move to me of Zduriencik’s tenure was designating O’Flaherty for assignment, considering that we continue to look for a left-handed reliever in his absence.

Since then, he’s been one of the best relievers in all of baseball — at least, one of the best if you’re going by ERA. In the past four seasons, O’Flaherty has the second-best ERA- in baseball among all pitchers with at least 200 innings: 49, second only to Mike Adams‘s 46. He’s ninth in WPA and second in REW (run expectancy wins), behind only Rafael Soriano. He’s super good. But he also has the second-highest gap between his FIP and his ERA, 1.19, second only to Darren O’Day. What explains that gap?

Well, first of all, his LOB%. Not coincidentally, he is also second to O’Day in strand rate. Second, he also has a slightly below-average strikeout rate, for which he compensates by getting a whole lot of ground balls: his career 54.4 percent groundball percentage leapt to 66 percent this year. Third of all, and he doesn’t give up homers: he’s tied with Jonny Venters and Brian Wilson for the second-lowest HR/9 in baseball since 2009. (Brad Ziegler is first.) That’s another reason xFIP is so unkind to him.

The playoffs are probably the single time when bullpens matter most. The Tigers’ current closer, Phil Coke, is a LOOGY who’s been Peter Principled into the ninth inning job due to the utter implosion of Jose Valverde. The most famous member of the Giants bullpen is the guy who’s been injured all year, and Valverde may have cost himself tens of millions of free agent dollars with his meltdowns this October. O’Flaherty has been better over the past four years than anyone in either of the World Series bullpens other than Sergio Romo — and yet he’s only made $6.2 million dollars in his nine-year professional career, including signing bonus.

He has just over four years of major league service time, so the Braves will get him cheaply for now. “Underrated” relievers don’t always stay underrated, as the Padres underscored when they traded Mike Adams for Joe Weiland and Robbie Erlin. O’Flaherty has real trade value: he could close for most of the teams in baseball right now, he’s still under team control, and he made just $2.5 million this year. The Braves may not trade him, but they certainly ought to consider it.