Why Wasn't Bobby Parnell Already Closing?

Your team has a 0.1% chance of making the playoffs this year. You have two relievers that you think could close in your pen. One is a 26-year-old with a triple digit fastball that is under team control until 2015. The other is a 38-year-old with a 91-MPH fastball and substandard stuff that will be a free agent at the end of the year. The decision seems clear.

Why did Jason Isringhausen even get a chance to record his 300th save? Why wasn't Bobby Parnell the closer the minute Francisco Rodriguez left town? Why is the team only transitioning to Parnell now?

Let's start with the first. Obviously, the story of Jason Isringhausen and his path from Generation K to celebrated closer to out of baseball and back to New York for redemption is a compelling tale. The man had tuberculosis at one point. He's had flexor tendon surgery, Tommy John surgery, two hip surgeries, and labrum surgery. And yet he's also saved more than 30 games and had a sub-three ERA seven times each.

He represents a compelling story, and he also has fans in New York that remember the promise of a forgotten generation of pitchers. These things mean butts in seats, don't they? Right now, the team ranks 13th in baseball in attendance per game (30,891) despite having a worse record than all but four of the teams ahead of them on the list. Keeping fans interested during a losing season requires story lines, and Izzy's march to 300 could fill that hole.

But it's unclear how important such a story might be. The Dodgers just told the worst story a team could tell: their leadership was robbing the team blind for personal gain while the product on the field declined to near-unwatchable. And yet, there they are, still ninth on the list and pulling in almost seven thousand more fans per game than the Mets. Even a comparison of attendance figures from before and after the bankruptcy filing found that attendance was not affected by the negative news. And the Dodgers are in a similar media market and have an American League competitor in town, so the comparison seems apt.

The other idea behind coaxing Isringhausen along to 300 was that Bobby Parnell was not ready to close and that he needed a caddy to help him along the way.

The statistic at play here is leverage index (LI). The stat takes account of the inning, the score, and the number of outs in order to figure out how important a moment is to the game. Over the full year, Parnell has entered the game in moments that are 1.12 times more important than your average moment. Isringhausen's number in that category is 1.56. In the last thirty days, though, Parnell is up to 1.53, so he's being used in more important situations. That would have happened with or without Isringhausen, but the elder statesman has taken the bullet for Parnell in the last thirty: his LI upon entering the game over that time period has been 1.92.

So Isringhausen has allowed the team to bring Parnell into the pressure innings slowly. That must have some value, if difficult to quantify. Now Parnell is showing the highest LI of his career and might be more ready for the 'transition' to the closer role that was coming for him all along.

And now we get to the most pressing question: can he close?

Why not? He hits triple digits on the gun with his fastball and has a slider that has been above-average by linear weights every year in his career. Only seven pitchers in baseball have averaged a higher velocity than Parnell this year, and one of them, Aroldis Chapman, profiles very similarly. They both are fastball/slider pitchers with control issues and double-digit whiff rates. If you asked if Aroldis Chapman could close for the Mets, the answer would be a resounding yes, most likely.

Chapman also walks almost twice as many per nine as Parnell. In fact, it's hard to tell why there's so much negativity about Parnell, even when it comes to his control. His 3.86 BB/9 is not great, but there are nine closers in baseball with a worse walk rate... including Isringhausen (for now). And his 2.88 K/BB puts him at 49th in the league in that category among relievers with more than 40 innings this year. His double-digit strikeout rate makes his iffy walk rate play. And he had a 3.9 BB/9 in the minor leagues, so this isn't some small sample miracle.

Mostly, Parnell has been unlucky. With a 49.5% groundball rate and a 11.12 K/9, he should have a much lower BABIP than .381. In fact, using Matt Swartz's research for SIERA, we can find his xBABIP using just these stats: .289. That's one hundred points of bad luck.

We've been calling for Bobby Parnell to close for some time here. And maybe it's not such a big deal that he hasn't been closing for the past two weeks. Even if it probably didn't have much of an effect on attendance, there might have been a non-zero value in easing Parnell into the role. Now that the big boy has gotten used to the eighth, though, it's time to get him out there in the ninth.

Oh, and it's also time for us to settle on a nickname, because all great closers have one of those.