Penny's fastball: A fluke, or a sign of things to come?

The question the Red Sox have to ask themselves, as they ponder the idea of trading Brad Penny to make room for John Smoltz, has nothing to do with the way Penny has performed so far this season -- and everything to do with the way he'll perform the rest of the season.

And here's the big question: If he's going to pitch the rest of the season the way he pitched on Thursday against the Yankees, would it be insane to trade him?

Well, yes, it probably would be. No matter what you can get from John Smoltz, it's not going to be much better than what Penny did on Thursday -- six shutout innings, five strikeouts, a 98-mile-an-hour fastball. The only line drive he allowed was the one Johnny Damon hit right at Kevin Youkilis in the first inning. It was the second time in four starts he'd allowed just one line drive.

It's the fastball, though, that piques the imagination. Penny has the veteran smarts to know what to do with a 98-mile-an-hour fastball, and if he can keep his velocity up there, he's going to be a valuable pitcher down the stretch.

The question is: Can he? Check out this chart, a measure of Penny's average velocity per start. (For some reason, we're having trouble uploading the chart into the blog itself, so it's probably easier to open the link in a new window.)

Thursday marked the first time Penny had finished a game with an average velocity over 95 since he won his 16th game in 2004, a five-inning outing against Arizona in which he likewise only allowed one line drive.

Since then, though, he's had to fight through shoulder issues that cost him most of last season and quite a bit of money on the free-agent market. He's shown glimpses of his old self this season, but Thursday was the first time he'd really let it fly.

The graph, though, does look a little ominous. His velocity had been fairly consistent all season before he ramped it up on Thursday -- and one has to wonder if the adrenaline of the Yankees as well as the understanding he was on the verge of being traded put a little extra on his fastball.

If that's the case -- and the graph certainly makes Thursday look like an outlier -- it might be worth trading him on Monday, the first day he can be traded without his consent, while his value is at its highest.