The Cubs today announced a little switcharoo in the rotation, which will have Tyler Chatwood set to make his season starting debut on Sunday (after his last would-be start was snowed out last Sunday).
Now the rotation looks like this: Kyle Hendricks today against the Diamondbacks, Yu Darvish tomorrow against the Diamondbacks, Tyler Chatwood Sunday against the Diamondbacks, Jose Quintana Tuesday against the Dodgers, Cole Hamels Wednesday against the Dodgers (Bastian).
My guess is part of the reason this wasn’t decided before today was uncertainty about whether/when Jon Lester could return in the Dodgers series, which would remove the need for Chatwood to make a start this weekend. The Cubs have at least closed the door on him returning for either of the first two games of that series.
You shouldn’t necessarily take that as me suggesting Lester’s injury is worse than expected or that his recovery is coming along slowly, but it’s one plausible reason for announcing the rotation as it was just a few days ago, and now making this change. If you realize you’re going to have to give Chatwood a start either way, better perhaps against the Diamondbacks than the Dodgers.
To that end, while the Diamondbacks have been below average against righties this year, they’ve crushed lefties. And the Dodgers have been the best team in baseball against righties. So, again, if you’re considering switching things around anyway, might as well do it this way and guarantee the Diamondbacks face all righties and the Dodgers face at least two lefties.