Quick stats on Olson:
ERA WHIP IP K BB 2006 Frederick 2.78 1.23 81 77 19 2006 Bowie 3.43 1.30 84 85 31 2007 Norfolk 3.46 1.06 104 94 31
He hasn't dominated at any level except for short-season A-ball in 2005, which he should have dominated since he pitched three years of college ball for Cal Poly.
Olson's best pitch is his curveball, which Baseball Prospectus called "one of the best in the minors" in the 2007 book. They also said that Olson was probably ready right now to be a lefty specialist reliever in the major leagues, which is a pretty good sign for a guy who hadn't pitched above Double-A yet and was 23 years old.
SB Nation's own John Sickels gave Olson a B grade, and rated him fourth in the Orioles system, behind Rowell, Erbe and Reimold, the last of which I greatly disagree with as I am not really a believer in Reimold at all. He called Olson a potential "solid mid-rotation starter," which is pretty much the idea.
The key to getting excited about the Olson call-up is pretty simple: Don't get overly excited. He's got 100 innings of Triple-A ball to his name and was good there, not great. Don't expect him to come up and make an immediate impact. But I do hope with Trachsel out that they keep him up for the time being, even if he struggles through it. There's no reason to shuttle him back to Norfolk in favor of Rob Bell, who has proven several times over that he's a bad major league starter. Olson should be given time to adjust to the change, and see what, exactly, needs to be worked on to get him ready for the major leagues, because he should be a real candidate for the 2008 rotation.
One thing I find strange is that between Cal Poly, Aberdeen and Frederick in 2005, he threw 190 innings at age 21, 136 of which were in college. The Orioles probably could have exercised a little more caution with his arm. Did he really need 40 innings at Aberdeen? Half could have proven the same thing, which is that he was definitely too good for the New York-Penn League.