No, Jonathan Papelbon isn't the pitcher he was two years ago. And yes, last night's loss was rough. But does that mean it's time to replace Papelbon with Daniel Bard? Well, (as Dave Cameron writes), maybe ...
Except, you don’t really want Daniel Bard on the mound against left-handed hitters in a high leverage situation.
This year, Bard has faced 78 lefties and posted a 4.56 xFIP against them. He has struck out just 12 while walking 8 (plus hitting another batter), which pales in comparison to the 27/4 K/BB ratio that he’s running against righties. He was better at blowing lefties away a year ago, but still struggled to throw strikes against them, and now sports a career 4.13 xFIP vs left-handed hitters.
Bard has good enough stuff to get lefties out, and in time, he could indeed be a quality ninth inning guy. But right now, the Red Sox are better off letting Papelbon work through his issues.
Cameron also points out that Papelbon's probably better than his (3.64) ERA and, presumably, his (2.08) strikeout-to-walk ratio, since 1) he's still throwing quite hard, 2) his swinging-strike percentage is right in line with his career rate, and 3) he's been throwing a lot of first-pitch strikes. Plus, we're talking about only 30 innings this season and you have to figure those six home runs he's allowed could (almost as) easily be three. In which case his ERA would look a lot better.
There's just one bit missing from Cameron's analysis: Papelbon's numbers against left-handed hitters.
They're awesome. Career-wise, he's been nearly as effective against lefties as righties. Given that the Sox don't have a reliable southpaw in the bullpen, they can't really play matchups in the high-leverage situations. Not effectively, anyway.
So I think Cameron's right. If Papelbon's struggles continue -- if he keeps giving up home runs, and can't get his strikeout-to-walk ratio closer to 3 than 2 -- they'll probably make a change. After this season, they'll probably have to make a change, because Papelbon won't be worth what his agent wants in a new contract. At this exact moment, though, he's probably still their best option in the ninth inning, most nights.