Remember back in spring training when we were all worried about Jonathan Papelbon's decreased velocity? It had been trending down over the past several years and he was barely hitting 92 or 93 in Clearwater? Remember the studies cited about decrease spring velocity being a sign of problems to come? Remember the concern? The worry? The teeth-gnashing?

Then remember how we all felt after his second appearance of the season? To refresh your recollection, on April 2, Papelbon entered the game in the ninth, when the Phillies were leading the Rangers 3-1. Papelbon faced 7 batters, walking 2 and giving up 4 hits. None of them were particularly hard hit, and one famously was the result of a defensive adjustment that Papelbon was none-too-happy about. But this was on Papelbon, as he had no control and walked in the winning run, getting only 1 out. Remember how shitty that felt? Remember how even our best reliever was going to be awful this season? Remember how we were all doomed?

Well, the Phillies are still doomed this season, but not because of Papelbon. He is having a great season. But have you stopped to realize just how amazing? We're only halfway through, but at this pace, it's quite possible that Papelbon could have one of the greatest seasons a relief pitcher has ever had.

First, a few basic numbers to give context. So far this season, Papelbon has a 1.27 ERA over 35.3 innings. Opposing hitters have posted a Michael Martinez-esque line of .179/.252/.195 against him. He has a 291 ERA+.

Even more stunning are Papelbon's numbers after April 2. If you cut out his first two outings (a scoreless inning on March 31 and the abysmal outing on April 2), Papelbon has been virtually unhittable. He has a 0.53 ERA in 34 innings. Opposing hitters have a .157/.224/.165 line, good for a .389 OBP. In other words, every batter against Papelbon is an opposing pitcher.

These are incredible stats that prove Papelbon's dominance this season.

But I want to focus on a particular stat that shows just how dominant Papelbon has been. Notice in the triple-slash lines above how similar the first and third numbers are. The first is batting average and the third is slugging. The difference between the two is isolated average, ISO for short. Basically, ISO tells you how much power a hitter has beyond hitting singles. For a pitcher, it tells you how much power opposing batters have.

Against Papelbon this year, opposing batters have virtually no power. Here are the stunning stats -- opposing batters have hit 2 doubles, 0 triples, and 0 home runs against Papelbon. In other words, in 35.3 innings, Papelbon has given up 2 extra-base hits. That's it - just 2. And both were just doubles. His ISO tells this story, as it sits at a miniscule .016.

To put this in historical perspective, I looked at all relief pitchers since 1961 (expansion and the earliest I could find keeping track of extra base hit types against pitchers) who have pitched 50 or more innings (Papelbon is on pace to throw over 70). Since then, there have been only two relief pitchers who have had an ISO of .020 or lower for a season - Frank Williams in 1986 and Jim Johnson in 2008.

For Williams, in 1986 he threw 52.3 innings and gave up just one double. Opposing batters had a .006 ISO against him, which is truly unbelievable. Williams had control problems though, and gave up more singles than Papelbon, as the .212/.314/.218 triple slash for opposing batters indicates. Nonetheless it was a truly remarkable season, the best by a relief pitcher ever in this regard.

In comparison, Johnson was much worse, though he was still historically special. Johnson pitched 68.7 innings and gave up 4 extra base hits, all doubles. He also gave up more singles than Papelbon and had control issues, with a .219/.305/.235 line for opposing batters. This works out to a .016 ISO, just like Papelbon's this year.

If Papelbon keeps his performance up, he'd finish the year tied with Johnson, as having the second lowest ISO for a relief pitcher since 1961 . . . . except for one thing:

Wade Davis. If Papelbon is having one of the greatest relief seasons ever by the measures here, Davis is having the greatest season ever. So far this season, Davis has pitched 37.7 innings and given up exactly zero extra base hits. You read that correctly - zero. As in zilch. As in, Davis has faced 148 batters and not a single one, all major leaguers, some quite excellent, has had an extra base hit. All told, Davis has given up just 15 singles. Opposing batters have an absurdly bad .117/.230/.117 line against him. That's just insane.

But getting back to Papelbon, for all the talk of how much many of us don't like him as a person (at least, what he shows publicly), how awful his contract is for the Phillies (and it still is regardless of this post), and how important it is for the Phillies future that he be traded this month, let's not fail to appreciate how historically special his season has been so far.