It's official. Davis will start the year as the Rays' fifth starter with Andy Sonnanstine as the long man in the bullpen. According to Maddon, this decision was prompted by J.P. Howell's status since Sonnanstine has flexibility and can be used against both righties and lefties. He also hints that Sonnanstine could be used in more high-leverage situations as the season progresses or fill in as a starter. This is similar to how the Rays used J.P. Howell in 2008, allowing him to start as a long man in the pen and then transitioning him to high-leverage situations as he proved capable.
Most projections peg Davis as a 4.00-4.50 Fielding Independent Pitching (FIP) pitcher and Sonnanstine projects to be around a 4.20-4.70 FIP pitcher, although most pitchers see a decrease in their FIP upon moving to the pen. Being used solely out of the pen could help Sonnanstine's stuff, allowing him to increase his velocity and strikeout numbers. Of course, not all pitchers perform better out of the pen (think Jason Hammel), but some can significantly benefit from the move (think J.P. Howell). If Sonnanstine proves to be merely a 4.00 FIP long man, though, he'll still be a valuable bullpen asset for the Rays.