Beware of Thomas Diamond's Return
Thomas Diamond is not returning to the major leagues this week -- he cannot return to a place he's never been. Instead, he's going to be returning to earth -- where he had been until this year. Because of the Lilly trade and because of the now ineffable resistance to moving Andrew Cashner to his rightful spot in the rotation, the Cubs have summoned the once-Texas Ranger Thomas Diamond from AAA to see if he can bring his nifty 3.15 ERA to the majors.
This will not happen.
Let's look at his numbers:
ERA FIP MLE FIP HR/FB% BABIP
Diamond, AAA '10 3.15 4.09 4.79 6.8% .270
Diamond's FIP (or Fielding Independent Pitching, a great predictor of future success) is good. It's -- in fact -- above average. However, if we use Minor League Splits' Major-League Equivalent algorithm, we obtain a much less exciting 4.79 FIP. This is below average. Still, if we assume that 2010 is a bust year for the Cubs, then at least we get to audition some young talent and see if we can find some, er, diamonds.
But that's not the end of the story, tragically. He also has been on the fortunate side of luck. His low HR/FB% and his BABIP indicate that he's nervously watched many should-be-home-run balls knick off fences or slip behind foul poles and should-be-hits lined into gloves of wide-eyed infielders. Using Minor League Splits luck neutralizing algorithm, we can expect that -- perhaps given a full season in AAA this year -- Thomas Diamond would end with a FIP closer to 4.39, or pretty close to average.
Average in AAA sadly and often means piss-poor in the MLB.
How much fun is it to watch James Rusell or Justin Berg pitch? If you answered, "Very fun!" then I've got some great news for you: Mr. Diamond will gave you the same fun every fifth day!
If for some reason you don't like watching Cubs pitchers turning around and watching balls sail through the night, then you might find watching Thomas Diamond somewhat of a tribulation.
This makes me ask: Why then not just move Andrew Cashner to the rotation? Perhaps this is a precursor to this move (bullpen pitchers typically have to build their durability before they can start), which I'd be okay with. But if not, then what about Sean Marshall, who already sports a nifty xFIP in the 2's and has improved immensely over the last three years. Moreover, the last time he was a full time starter -- some three years ago -- he gave us an acceptable 4.50ish xFIP, which is the absolute best and most optimistic output that Diamond will give us.
Oh well, these are just the statistics, and since when have the Cubs listened to the statistics?