With Justin Verlander and Edwin Jackson as the solid one-two combo at the top of the rotation, and the emergence of 20-year-old rookie Rick Porcello, the top three spots in the rotation are set. But the question becomes who will fill the other two slots?

Armando Galarraga was the Tigers best starting pitcher last year, his first as a starter. Galarraga went 13-7 with a 3.73 ERA last season, but has struggled this year going 3-7 with an ERA of 5.56. He won three of his four starts in April, but since then he has gone 0-7 with a 6.07 ERA. One key stat that has changed this season is his WHIP (Walks and Hits per Inning Pitched). Last season it was 1.19, but this season it has jumped to 1.61, meaning he is giving up almost half base runners more per inning.

Another candidate for the starting rotation is Dontrelle Willis. Willis started this season on the disabled list for what was described as an anxiety disorder. Some of his anxiety may be due to his inability to throw strikes, as he has 63 walks in his 15 starts as a Tiger. In comparison, the most walks Willis gave up in his years in Florida were 87 in 35 starts for the Marlins in 2007. The Marlins saw that he was beginning to lose his control and forced any team that wanted Miguel Cabrera had to take Willis as well.

Reports have come out saying Willis will not make his next scheduled start on Saturday against the Milwaukee Brewers, and manager Jim Leyland refused to comment on why. It appears that Willis may have made his last start for the Tigers this month, if not this year. He signed a three year contract worth over $29 million two weeks after being acquired from the Marlins and is currently in his second year of the deal.

Jeremy Bonderman was another candidate to fill a spot in the rotation, but recovery from surgery to remove a blood clot that he had last season has put a damper on his 2009 season. He returned to make one start this year, but was put on the disabled list June 9th and is not expected back until September at the earliest. Bonderman is missing his first substantial amount of time in his career, and it will be important to see how he returns from this injury later this season to determine his status for this year and beyond.

Pitchers from the bullpen that could win a spot in the starting rotation include Zach Miner, or Nate Robertson. Miner has pitched decent this season, allowing only one run in his past 11.2 innings of work. He also has started four games for the Tigers this season going 2-1 with a 4.74 ERA in those games. Robertson had been in the starting rotation since joining the Tigers in 2003, but his ineffectiveness last season cost him his job. He has struggled for the Tigers in the bullpen and his odds of getting a start are slim.

Currently it seems that Galarraga will get at least one more start to try and work out his problems, and the other spot will likely be filled by either Zack Miner or either Luke French or Ruddy Lugo from Toledo. French and Lugo both are having solid seasons in Toledo with ERA’s below 3.60. Whoever takes Willis’s spot in the rotation could become a regular in the rotation with a few solid outings.