Kyle Massey -- Thinks Bristol Palin 'Fight' Was a Setup

Bristol Palin's run-in with a heckler was set up by the producer's of her reality show -- at least that's what her co-star Kyle Massey thinks ... this according to sources close to Massey.

Palin got into it with a guy named Stephen Hanks at a bar on the Sunset Strip Thursday night. Hanks told us it was NOT a setup, but we're told Massey doesn't buy it.

According to our sources, Massey -- who is starring with Bristol in a reality show for the BIO Channel -- feels it was a little too convenient that so many cameras were there to catch the confrontation.

Our sources say Massey feels the producers of the show were behind it all, but that Bristol had NO part in it. We're told Kyle feels that Bristol would never have agreed to something like that and that Bristol has been nothing but genuine and honest with Kyle so far.

According to our sources, Massey is not happy with the direction the show has taken. We're told Massey feels the show is now "sleazy" and thought he was signing on for a scripted show ... and not a reality show.