Freddie Kitchens Screwed Up But Don't Fire Him Yet, Says Brandon Marshall

Brandon Marshall is calling for MERCY for Browns head coach Freddie Kitchens -- telling TMZ Sports the guy should get another shot in Year 2 ... with one serious caveat.

Of course, calling the Browns underachievers under Kitchens is a massive understatement ... they've got an insanely talented roster but have only managed to get 5 wins.

And, after Kitchen rocked a "Pittsburgh Started It" shirt -- making light of the Myles Garrett helmet attack days before the Steelers rematch -- many are calling for the ax.

But, not Marshall ... at least, not yet.

"I didn't like him wearing that shirt. It made no sense for him to do that. Nothing that justifies that," Marshall said ... "But, I hate letting a coach go in the first year."

Marshall suggested keeping Kitchens around for a Prove-It year 2 ... but "he's gotta turn it around" -- explaining there's a serious problem with the culture in Cleveland.

"There are some cultural things he's gotta fix."

As for Baker Mayfield, Marshall's optimistic about him too ... saying it appears the QB has turned a corner and is starting to show he can be the guy in CLE.