While having more pitchers available than you can fit into the rotation is usually considered a good problem to have it is still a problem that must be sorted out. The first step was taken yesterday with Jeff Niemann being returned to the Durham Bulls; although it was a shame that he only was able to make two starts he was the obvious choice due to him originally being up to replace Garza and also because the other three pitchers in contention for the rotation spots were ahead of him in line for evaluation. Another good start might have forced the Rays to make a harder decision but that just wasn't to be; he may have been going back down anyway no matter what he did.
That leaves the trio of Jason Hammel, Edwin Jackson, and Andy Sonnanstine left for the two spots that will remain available after Kazmir's return at the beginning of May. Before I say anything else I should make my potential bias clear though I will do my best to be utterly objective in my analysis: I'm no Jackson fan, I didn't like him starting last season in the rotation, didn't like him staying there all year, and am not exactly thrilled that he's still in there. He hasn't been worth anything in the past four seasons at any level and in my opinion isn't close to suddenly becoming good. I am a Sonnanstine believer, I think that given time in the majors to adjust he can be an averagish innings muncher though his upside is limited due to his low velocity. As for Hammel, I've believed in him for years and haven't stopped believing in him at any point, though I'm one of a very small minority that felt good about him being in the rotation to start the season.
With that out of the way, the relevant numbers for the gentlemen so far:
The one thing that stands out immediately is that Hammel has clearly been the best of the three so far, although he has had one fewer start to succeed/fail in. He has yet to have a start that could be considered poor (four runs in six innings on the road against the Yankees is quite decent in my eyes) and barring a complete and utter meltdown in his two remaining starts before Kazmir's return he almost certainly has a spot locked up and deservedly so. He has upside as well, his fastball can reach the mid-90s, his curveball is inconsistent still but has massive break when it's on, his changeup is ok, and he has above average control.
That leaves Sonnanstine and Jackson, two extremely different pitchers who have had similiar major league results in the category that really matters in the end: runs allowed. Neither has performed well and either of them could justifiably lose their rotation spot; Jackson's hot start was quickly erased by two generally incompetent performances that looked a lot like last season and Sonnanstine has one gem, one decent start, one mediocre one, and one in which he got bombed all over the place.
The case against Sonnanstine
He doesn't throw very hard and has a tendency to pitch up in the zone, not just in the majors but in the minors as well. Without a successful change in approach he can't succeed as a starter and through 155 innings he hasn't done much to fix that problem. His lack of velocity or an outstanding secondary pitch means that he has to have great control AND command if he's going to consistently get major league hitters out. He also has options remaining and therefore can be sent to the minors at any time, plus his strike-throwing approach may be suited well to short relief if he goes to the bullpen.
The case against Jackson
Jackson has always had a reputation for great stuff but thus far in his career he has peaked at 19 and been a mess since then. He is plagued by control problems, sometimes showing a complete inability to throw the ball anywhere near where it needs to go, and despite his strong arm and good slider he hasn't put up the strikeout totals you'd expect and that he needs to succeed with spotty control. His first two starts of the season were an anomaly compared to his career as a whole and his "successful" second half of 2007 was merely a result of him no longer getting bombed and also having some good luck; his strikeout and walk numbers were still shaky and portended future failure. The Rays have been giving him chances since 2006 and he disappoints every time.
That's the facts for the two, now here's an opinion. I think Jackson should be traded for whatever can be gotten for him or just DFA'd once Kazmir comes back, unless the Rays are unsure of the continued health of both Kazmir and Garza in which case it would probably make more sense to bury him in the bullpen for a little while. Everytime he shows something good he quickly returns to being lousy, I don't think he's going to suddenly figure it out anytime soon and become even an average starting pitcher. The Rays have given him 36 starts and 23 relief apperances and all too few of them have been productive. Sonnanstine doesn't have a big fastball or a dominant breaking pitch but he's a smart guy with great control and a pretty good idea of what he's doing out there, he needs to make adjustments but they're adjustments that he should be able to make.
However, if I had to guess what will happen when Kazmir comes back, then assuming that the situation stays basically the same (meaning that neither Sonnanstine or Jackson obviously wins or loses the spot in the two starts each of them have coming) I think Sonnanstine will either go to the minors or the bullpen, forcing us to continue to watch Edwin Jackson fall short of the hype for the fifth straight season. I don't know about you guys but I'm really tired of watching him pitch.