If you are going to use Roman numerals for the small numbers, then you have to use them for the big numbers too. Your sentence should read as follows:
"Hoyer was an undrafted free agent out of Michigan State (where he was Honrable Mention All-Big Ten in MMVII). He appeared in XIII games for the Patriots from MMIX to MMXI, and was XXVII of XLIII for CCLXXXVI yards, I TD, and I INT."
Would have been perfect if you had mentioned that he played in the Big X conference.