Either Valde Garcia or current State Sen. Joe Hune (who is only in his early 30s, Garcia is in his late 50s) would seem the most likely, unless there are other names from the private sector or lower office. Hune would have to give up his seat to run, however.
“Hune would have to give up his seat to run, however.”
Yeah, Hune’s Senate seat is up in 2014. But Hune might be willing to risk it, since (i) it would be his last term in the MI legislature anyhow (he already served 8 years in the state house and if reelected to the state senate in 2014 he’ll reach his two-term limit there as well), and (ii) if a Republican wins the MI-08 seat in November (which is the likeliest scenario, particularly since Democrat hottie Gretchen Whitmer almost certainly will pass up a run, as she has prior entreaties to go to Washington or even to run statewide), it may not open up again for a while, and Hune would then have to risk a statewide run if he wants to stay in elective office. Given that Hune first got elected to the state house at age 21 and has been in elective office ever since, I have to assume that he’s very ambitious and would be hard-pressed to pass up this opportunity, even if he has to face Valde Garcia or another top-tier Republican in the primary.