Aaron Cook's 2012 season is fascinating. Don't confuse that for good, because it hasn't been that, especially as of late. But there's no denying that it's been an intriguing year for baseball fans to appreciate for its oddness. Cook has thrown 44-2/3 innings, and has just four strikeouts on the year. At the same time, though, he has handed out just four walks, giving him strikeout and walk rates of 0.8 per nine.
Were the season to end for Cook today, he would have the second-most innings ever with fewer than both one strikeout and walk per nine innings. Only Slim Sallee, a pitcher nicknamed "Scatter" for a reason, finished a season with more, when in 1919 the right-hander tossed 227 frames.
Sallee pitched at a time when women had just received the right to vote, there had only been the one World War, and the game was chronologically closer to banning black players from the league than it was to integrating. The Black Sox scandal occurred that season, Boston had just won a World Series the year before, and the Cubs were just over a decade removed from their last. It would be 60 years before Aaron Cook was even born, never mind that it was another 23 years before he even pitched in the majors, and another decade before we hit the present.
Much changed in that time frame in the world and in the game, and one of those changes was just how good and powerful hitters have become. Sallee could persist -- succeed, even -- with the kind of conditions he pitched under in 1919. For his career, he owned a 1.5 K/BB ratio that stemmed from 2.7 strikeouts per nine against 1.8 walks per nine, and finished with a 114 ERA+ despite this. He had fantastic control, failing to walk more than two hitters per nine innings for the last seven years of a 14-year career, and eight of his total seasons featured a sub-two walk rate. As for the strikeouts, they were low, even for the time period, but the average punch out rate in 1919 was 3.1 per nine, or nearly 4.5 strikeouts per nine lower than today's average.
As such, it's not shocking to see that, while Sallee posted a home run rate of 0.2 per nine both in 1919 and for his career, Cook has given up twice as many homers as he has free passes and punch outs combined. Today's game punishes pitchers far more for pitching to contact, and while that's certainly a viable approach, Cook has taken things to an extreme that is far too volatile to rely on in today's game. More strikeouts and more walks would likely fix a lot of what's wrong with his season, but given that he is pitching in a way that intentionally brings about these results -- well, not the homers, as those are a byproduct rather than an intended consequence -- it's hard to count on things changing.
Just three percent of Cook's pitches have induced a swing-and-miss. However, 67 percent of his pitches have been strikes, with 18 percent looking. That's a massive amount of balls in play, and even if Cook has just a .249 batting average on balls in play for the season, with the sheer volume of balls put into play, there are going to be runs scored against him. Look no further than his rate rate for evidence of this: opponents might only be hitting .249 when they put the ball in play, but since they do it so often, he's giving up over 10 hits per nine innings, and owns a 1.21 WHIP in spite of a sub-one walk rate.
Due to Cook's history of success as a starter, you could normally live with him in the rotation and hope things improve for him enough that he can be a little closer to average. The Red Sox don't have the luxury of waiting, though, as they're 3-1/2 games back of the wild card with less than two months of baseball left. They also have a replacement already on hand in Franklin Morales, who certainly has no issues missing bats.
Should Josh Beckett's back prove healthy enough for him to take his next turn in the rotation, then there's no reason for Aaron Cook to remain in his spot. The Craig Breslow trade gives Boston two left-handed options out of the bullpen, freeing Morales up to start once more. Cook can assume the long man slot that Morales currently occupies, leaving him stretched out enough to start without compromising either the health of his shoulder or Boston's starting depth.
Cook still has his sinker, and it's an effective pitch, but it's about all he has left to him. The fact nearly 80 percent of his pitches have been sinkers -- the highest rate he's ever thrown in his career -- shows that even Cook is aware of that. Less might be more with Cook from here on out as long as Boston remains in the race, and given the team's talent, that could be right up until season's end.