"Robert had some fundamental flaws," Gruden said. "His footwork was below average. He took three-step drops when he should have taken five. He took a one-step drop when he should have taken three on a couple occasions and that can't happen. He stepped up when he didn't have to step up, and he stepped into pressure. He read the wrong side of the field a couple times.
"So, from his basic performance just critiquing Robert, it's not even close to good enough to what we expect from the quarterback position."
Gruden mentioned Griffin missing on multiple deep-ball throws to DeSean Jackson, noting it as a big difference in the game.
"(Josh McCown) hits Mike Evans three times for big, huge plays, and we missed DeSean three times for big, huge plays," said Gruden. "Flip 'em -- if Josh overthrows Mike, and we hit ours, I'm a little happier right now."
Gruden was also asked about postgame comments in which Griffin said a quarterback only plays well if his teammates do their job. Jackson appeared to respond to Griffin's comments with a pointed Instagram message.
"First of all, Robert needs to understand he needs to worry about himself No. 1 and not everybody else," Gruden said. "... It's my job to worry about everybody else. Yes, everybody else needs to improve, but it's not his place. His place is to talk about himself and he knows that. He just elaborated a little too much and he'll learn from it. He's 24 years old."
Gruden's frank comments stuck out to NFL Media analyst Nate Burleson, who was stunned he spoke so candidly about his quarterback in a public forum.
"You know, usually that stuff is said behind closed doors," Burleson said. "He might just get up there and say, 'Our quarterback didn't play well enough today.' But you don't go out there and break it down and actually expose every single thing that the quarterback did wrong."
Brian Baldinger added on NFL Network's The Aftermath: "I've listened to a lot of postgame press conferences over a lot of years, and I've never heard a coach criticize his quarterback like that."
Griffin played poorly against a bad Bucs team, then compounded matters by saying the wrong things to the media. Now Gruden has to clean up the mess -- and he doesn't sound happy about it. RGIII appears to be on thin ice with the franchise that once saw him as its savior.