Gordon Edes has a good look at the options available to the Red Sox for their 2013 starting rotation.
Its interesting that Edes doesn't view Alfredo Aceves as a persona non grata with the Red Sox and actually considered him a viable option for the starting rotation. I would think John Farrell would be best served eliminating any headache players from 2012 with Aceves at the top of the list. Aceves is still under team control and will probably only cost a little more than $2 million in arbitration - I'd be dangling him in trade talks.
Also interesting that he doesn't even mention Vincent Padilla as an option. Padilla would be relatively inexpensive to keep and did average more than a K per inning in 2012. He came into town with a bad reputation but he was a solid citizen whose stock with fans went way up as he was one of the only players to attend Johnny Pesky's funeral.
If the Red Sox keep John Lackey then they would have a rotation of Jon Lester, Clay Buchholz, Felix Dubront and Lackey. If that's the case then they have a number of young arms that could step up to be the number 5 starter or fill in if there are any significant injuries.
My preference would be to trade away John Lackey and bring in either Dan Haren or Cliff Lee (if the Phillies are looking to move his contract). Fangraphs has a very good look at Haren whose option may not be picked up by the Angels. It should be noted that 2012 was a bad year for Haren but his 4.33 ERA still would have been the better than any Red Sox starter with more than 10 starts last season.