Jerome Bettis says he's having a hard time believing Big Ben is the problem in the Antonio Brown drama ... telling TMZ Sports, "That's one that I would need to see it to believe it."
"I know Ben," Bettis says ... "He's a standup guy. I'd have to see that for myself."
Remember, A.B.'s been encased in Steelers drama for the last few MONTHS ... and it seems his relationship with Roethlisberger is the source of it all.
In fact, Brown recently tweeted of the Pittsburgh star QB, "He has a owner mentality like he can call out anybody including coaches.