Jeff Locke is a better pitcher than his record indicates. But he may not be as good a pitcher as the Pirates will need in 2013-14.
Locke is a lefty, with good stuff. In this regard, he is like Paul Maholm in his earlier years. Locke's pitching is very polished for a rookie and therefore accomplished—for the minor leagues, that is.
In the majors, good batters can figure him out and find ways to get hits. That is a problem that Locke, like Maholm, can cure over time with more experience.
One of Locke's problems—a weak Pirates defense—shouldn't really be his responsibility. The bottom of the third inning in Wednesday's game against the New York Mets was a good example.
There were several defensive miscues, bobbled balls, bad throws, etc. that allowed runners to reach base safely and ultimately to score that stopped just short of being classified as errors. (On the other hand, Maholm recorded a large number of unearned runs in his early games.)
Therefore, four earned runs were recorded in the inning, but a more stringent definition of errors would have turned at least three of those runs into unearned runs. That would not have changed the score or the result, but it would have lowered Locke's ERA, and thereby made clearer his virtues as a pitcher.
Locke's FIP (sabermetric ERA) of 4.62 is decidedly better than his actual ERA of 6.35. According to FanGraphs, he strikes out a batter almost every inning while giving up only two walks per nine innings. He's given up two home runs per nine, which isn't so good, but is acceptable, given his other stats. (These are the variables plugged into the FIP formula to normalize a pitcher's ERA for random events.)
That's because the modern view of a pitcher's job is 1) to keep the ball in the park (few home runs), 2) keep the ball over the plate (few free bases by walks) and 3) to try to "miss bats" in doing No. 2, leading to strikeouts. Locke actually does both of the latter two quite well.
Pirates' management has not always seen things this way. Their theory, increasingly regarded as old-fashioned, has been that through location, spins and other techniques, pitchers should throw the ball in ways that make it easy for the fielders to handle if hitters manage to take a bat to them. Through this view, Locke is a "soft tosser."
One issue with Locke (that was also true of Maholm) is a "last inning" problem. That is, a pitcher is fine for X innings, and suddenly collapses one inning after that number (as Locke did in the Mets' third). For this reason, Locke looks like a (long) reliever who needs to build some endurance before he can be a good starter.
Like Maholm, Locke could eventually rise to "second starter" caliber. But even if the Pirates keep him, he might not be any where near second starter (unlike Maholm). By 2015, the Bucs could have Gerrit Cole, Jameson Taillon and Luis Heredia, all (presumably) first-starter types in the one-two-three spots, with the back end being filled by second-starter caliber Locke and James McDonald. Wouldn't that be a rotation?
But the greater likelihood is that the Pirates will trade or release Locke, without appreciating his virtues. He will get there on a timetable that the team won't understand—and probably won't be given the leeway that Maholm was.