According to Sherdog it will be Charles "Chainsaw" McCarthy:
"The Ultimate Fighter 3" winner's first opponent will be fellow TUF alumnus Charles McCarthy. Sources close to American Top Team confirmed to Sherdog.com that the fight will take place in London, England on March 8.
If you look at the fight you have McCarthy who is 10-4 with all 10 wins coming by submission against Bisping who in his last 2 fights the best thing you could say about him was "man, you just can't keep him on the ground." McCarthy also lacks the kind of takedowns Bisping was having to deal with in the fights with Hamill and Evans.
What you'd really like to see from "The Count" is some more aggression on the feet. In his two last fights he has been outstruck at times by guys with a "wrestle first" mentality, and that seemed to stem from an unwillingness to push the pace. This should be a win for Bisping but he has to do more than just win to restore his credibility as a "future star" in the UFC.
Should he look impressive against McCarthy I don't think it's out of the question to see Bisping/Franklin toward the end of summer/start of fall. Franklin needs a decent "name" to fight and Bisping will need to take on a real challenge at MW if he is able to dispose of "Chainsaw" with ease.
Of course in this game that "if" should be in bold and underlined. McCarthy is going to be looking to have Bisping tapping out and regretting shedding those extra 20 pounds.