Dunio : What's Wrong with Jeff Locke?

After dominating the first half of the season and making the NL All Star team, Jeff Locke appears to be an anti-All Star when he takes the hill now. In Locke's last 5 starts, he's pitched to the 4th inning or less 3 times and pitched 5 2/3 innings twice.
In Locke's last 5 games, he's pitched a total of 22 innings. He's allowed 19 ER, 15 BB, and 37 hits in this time frame.
I'd like to say fatigue is part of the problem given that Locke is very near the most IP for a season in his career. However, his fastball velocity seems consistent with where it was early in the season.
It's hard to say what's going on with Jeff, but the Pirates need to consider placing him on the 15 day DL to try to get him right for the last few weeks of the regular season. I'd be in favor in letting Jeanmar Gomez or Brandon Cumpton make a spot start or two in Locke's absense, but either way - something needs to change.