Baker Mayfield Has One of the Greatest QB Debuts Ever, NFL Network Analyst Says

Baker Mayfield's first game as a Cleveland Brown wasn't just impressive ... it was ONE OF THE GREATEST STARTS EVER -- so says NFL Network analyst Brian Baldinger.

Baker took over for starter Tyrod Taylor at the end of the 1st quarter of Cleveland's game against the NY Giants Thursday night ... and lit it up -- chucking two TD passes.

Baldinger -- who had a long NFL career as a lineman in the '80s and '90s -- was floored ... calling it afterward, "one of the greatest rookie quarterback debuts I've ever seen."

"This ability right now just to be able to make this throw to the sideline -- like, the throw is ridiculous," Baldinger says of one of Mayfield's highlights.

Baker's coaches had been steadfast earlier in camp that he's the backup to Tyrod ... but it might be tough to keep that same spiel up now.