The latest comes from Tennessee's receivers coach, Shawn Jefferson.
"He is deadly accurate," Jefferson told ESPN.com. "I am just giddy about his future going forward ..."
"He's the real deal. A couple years ago I was back in Detroit and when Matthew Stafford stepped into the huddle the first time, once I heard his voice and the way he called a play, I said, 'OK, that's a real one right there.' Same way with this one. He's real. He's got the goods.
"No. 1, it's his accuracy," Jefferson said. "No. 2, he's come in and grasped the offense. And No. 3 is the way the guys respond to him, the way he's able to go in that huddle and take control."
Jefferson said Mariota has already developed a rapport with all the receivers and that guys are fighting to get to the head of the line to play snaps with him "because they know the ball is going to be put right on the money."
Monday's OTA practice was rated as awful for the offense by a number of players, including left tackle Taylor Lewan and receiver Kendall Wright. But while it wasn't Mariota's best day, he's previously drawn compliments for showing good anticipation and finding a way to get the ball into tight windows, for his efforts in taking command of the huddle and for effective work on the move.
"The thing that he does well is he throws the ball right when you come out of your breaks," tight end Delanie Walker said last week. "For receivers, that's what you want. That gives you an opportunity to get the ball before the defender can break on us. He does some good things."
Lewan and Wright said the offensive bounce-back at Tuesday's OTA practice, which was closed to the media, would be big. On The Midday 180 in Nashville Tuesday afternoon, Lewan said the practice he and the team had just finished was much better.
The media will be permitted to watch Wednesday's practice, and Mariota will discuss it afterward.
The Titans have been encouraged by how quickly Mariota has picked things up.
"There hasn't been any point where we've said, 'OK guys, this is too much,'" quarterbacks coach John McNulty said recently. "He's been eating it up pretty quickly."