But what happens if you look at the individual performances of the projected rotation? Start with Pelfrey, Diamond, Correia and Worley . Add Cole de Vries as a fifth starter since he was the best of the rest for the Twins last year. Now assume all five stay healthy, start 32+ games and pitch at the same average rates they did in 2012, using Pelfrey's 2011 season since he hardly pitched last year. You end up with a major league average starting staff in terms of earned runs and innings pitched.
Starting with a league average pitching staff based on the previous season is not exactly an indication of a championship team. But here is how that list of 2013 starters compared to last year's starters, based on their 2012 (2011 for Pelfrey) performances projected to a full season:
Of course, its unlikely those five pitchers can be expected to stay healthy and produce at 2012 levels. The only thing that is really expected in baseball is the unexpected. This is just a starting point. They may do a lot worse, but they are just as likely to do a lot better. Diamond and de Vries had career years last year. But they are young enough that they could improve as well as regress. The numbers used for the other three were all at or below their career averages. Again, there is room for improvement.
The Twins will probably use 6 or more starters and this doesn't consider their depth behind these five. The Twins have a lot of pitchers competing for the 5th spot. That includes Kyle Gibson and Rich Harden, who could easily improve on the above group.
But the notion that the starting rotation is a big question mark is, well, questionable. The Twins have a pretty solid rotation to start with. Hand wringing about the Twins' rotation based on last year's lousy performance isn't warranted. The guys who created that mess are almost all gone.