Jonathan Papelbon has had a rough start to the 2010 season once you look past the surface. His current ERA is just 3.00, which seems high but only in a Papelbon-relative sense, given it would be his career high, but there are reasons to believe that he will finish the season worse off than that.
Papelbon is whiffing just 7.1 batters per nine, well below his career rate of 10.2 and almost half of what the Red Sox got out of him back in 2007, when he struck out 13 per nine. The past few seasons have seen Papelbon change his approach and lose some strikeouts along the way. A certain Baseball Prospectus author—we'll call him Marc N. (no, that's too obvious. We'll call him M. Normandin)—wrote in the 2009 annual that Papelbon may have problems in his future given these changes:
At times, Papelbon is a one-pitch closer, since he mostly throws fastballs, with only the occasional splitter to finish off a hitter. That trend was even more pronounced in 2008, as Papelbon threw even more fastballs, partially to combat the lack of swings and misses on splitters in the dirt. His declining strikeout rate reflects the change in hitters' approaches to the pitch, but he compensated by dramatically improving his ground-ball rate. The dip in splitters and wasted pitches dropped his pitches per plate appearance from 4.1 to 3.8, which also helped him lower his walk rate. As long as he displays this level of control, Sox fans will have nothing to worry about.
The emphasis at the end there is my own, and with good reason: Papelbon is walking 4.5 hitters per nine at present. Now, there are some problems with getting too worked up about this at this stage, as Papelbon has faced 100 batters, and you need around 550 for walk rate to stabilize, but the early trends are not looking good. See the above, where Papelbon threw more fastballs in order to "combat the lack of swings and misses on splitters in the dirt"? He's throwing his fastball a bit less this year in order to work a few more sliders and splitters in (the highest rate of splitters he's tossed since 2007, in fact):
His splitter is thrown low, and generally out of the strike zone. Conversely, his fastball and slider are generally up in the zone, which may explain some of that 1.5 homer per nine rate these first two months. It doesn't help that his fastball has been worth -0.6 runs so far either, considering he's averaged almost 19 runs with it per year since 2007.
It's odd that he's not picking up more strikeouts though, for a few reasons. First, hitters are swinging at far more pitches out of the zone than they were in 2009 (35 percent, which is well above his career level as well) and are making less contact with those pitches. He's also throwing first-pitch strikes 71 percent of the time, which would lead the league if he qualified (Cliff Lee, the current leader, is at 70.3 percent, and only Carlos Silva is also above 70).
There's a problem though, which is that opponents are making more contact on the pitches he does throw in the zone—he's right around the league average on that so far, which has never been a problem for Papelbon in the past. The additional contact has helped him to a .198 BABIP (thank you, Boston defense) but given his components, SIERA has him at 4.69, which is not a pretty place to be if you're a starter, never mind a reliever.
Papelbon is now missing more strikeouts than he was, not inducing grounders at the high rate of 2008, and has the worst control of his career going. It's just a 24 inning sample, but given he won't even get to 70 innings pitched, he's going to need to sort things out sooner than later in order to remain effective in his role, lest regression catch up to him. If you can get equal value for him in a deal, he may be worth shopping—if he returns to form, you got something great back in return, but if his ERA ends up ballooning because he fails to adjust (we're talking about a pitcher who thinks changing speeds is throwing a faster fastball, after all) then you win twice.