WEEI.com's Rob Bradford describes the throwing session that got the Red Sox excited about John Smoltz:

The Sox' contingent didn't know what to expect in the 50-pitch side session, perhaps just a stream of straight balls and a subsequent physical examination. But, with his agents also looking on, Smoltz first threw a few 40-yard passes and then picked up a slew of worn baseballs he said "had a mind of their own."
Finally came the first pitch.
"I'm standing back there ready to get this warm-up pitch," Scherer remembered. "Then, all of a sudden, here comes this 92 mph fastball, low and away, that doesn't touch my glove. I immediately thought, 'I better get down now. He's ready to go.'
"The way it came out of his hand … it shoots out of his hand. The thing I was amazed at was when he was warming up. I've seen him pitch a ton of times, but then I saw him warming up throwing the football back and forth and he's launching it halfway down the field. Then he's barely throwing the baseball and it's coming out there at 90 mph."
But, much to the surprise of the Red Sox observers, there weren't just the fastballs. Along came Smoltz's trademark slider, with the tight, late break, and some changeups and curves, for good measure. This wasn't what any of the onlookers were expecting.
"He starts mixing in his slider, and I'm like, 'All right, it has a nice late break and it's hard,' " Scherer said. "But then he was like, 'Now I'm going to throw a curveball,' and he breaks off this 12-to-6 that totally fools me. And then he starts saying we're going to throw split-fingers, changeups, and a little of this and that. I'm like, 'Good Lord Smoltzy, you're ready to pitch, aren't you?!' "

There's more in this vein. Read all of it, and you'd figure Smoltz for an Opening Day perfect game.

And then you read ShysterBall, who says it's a lot of BS. Why?

It's not BS because it didn't happen. In fact, I'm sure that it did. Why am I sure? Because Smoltz is basically superhuman and I have no doubt that he could break off 12-6 curveballs and fire fastballs with outrageous action if he were a double amputee.
But that's the problem. Basically every single time Smoltz had to shut it down with Atlanta it was the same thing: outrageously good pitching -- snapping slider, exploding fastball, knee-buckling splitter -- followed by a DL stint because it just hurt so damn much for him to do it. This is to say that unlike so many hurlers, Smoltz's injuries were not presaged by fat pitches up in the zone and serial shellackings. Smoltz is part machine. He is able to work through pain and keep his mechanics flawless. If he can't, he is able to adjust his delivery so lessen the pain and remain effective.
But only to a point. Eventually the pain becomes too great -- pain that most pitchers never experience because they aren't tough enough to pitch hurt as long as Smoltz can -- and he has to shut it down. When Smoltz is hurt, no one knows it until he tells someone, and while I don't intend to impugn his integrity or anything, I'm sure he wouldn't tell anyone on the Red Sox that he was hurting in a tryout situation like the one described in the article.
Because I love the guy, I hope he is lights out for the Red Sox. Because I have seen him so much, however, I would not at all be surprised to see him throw [eight] shutout innings with 16 strikeouts in his first game and then be shut down for the rest of the year immediately thereafter.

Craig knows Smoltz better than I do, but I will point out that he has not been particularly fragile. Until he reached his early 30s, Smoltz was almost completely healthy. He was a little shaky (though quite effective) in 1998 and '99, then missed the entire 2000 season with an elbow injury. He returned in 2001 and gave the Braves four good seasons as a reliever, then moved back to the rotation in 2005 and averaged 223 innings over three seasons.

Then he missed most of 2008. Smoltz turns 42 this spring, and he's not likely to figure into the Cy Young balloting next fall. But I think there's a pretty good chance that the Red Sox wind up getting their money's worth.