Like a skilled interrogator baiting a witness, Jon Gruden asks Marcus Mariota to diagram, step by step, the quarterback’s progressions on one of the University of Oregon’s trademark pass plays, "Bubble Y Over."

Then, as soon as Mariota lays down the marker, Gruden pounces, noting how the Heisman Trophy winner deviated from the script against Michigan State.

"We just went through the thing on the board, Marcus, why didn’t you throw it (to the) hot (receiver)?" Gruden asks.

But before Mariota can answer, the Monday Night Football analyst acknowledges, "You make one helluva play!"

It is a telling moment in this season’s "Gruden’s QB Camp" that debuts on ESPN on Tuesday, saying a lot about how Mariota, on instinct, can make game-turning plays even when he wanders from the blueprint.

The play, as Gruden points out, "is one of the signature plays of your career."

In it Mariota somehow evades a two-man blitz from his right, staggers to keep his balance while running to the left and shovels the ball to Royce Freeman for a key first down, rallying Oregon for a 46-27 victory over the Spartans.

In a video clip preceding the play, Gruden spotlights a Spartans assistant coach alerting the defense to precisely the play that is coming and declares, "They had the right blitz called, I mean, they brought two (defenders)."

MSU coach Mark Dantonio said afterward, "We had him (Mariota) dead to rights and he got out. We had him. I even said, ‘He’s sacked.’ "

A fixture of pre-NFL Draft coverage, "Gruden’s QB Camp" is part inquisition and part spirited give-and-take with some workouts at ESPN’s complex in Orlando, Fla., thrown in for good measure.

It is a smiling, laughing and, at times, wise-cracking Mariota, attired in a Nike "Hawaii" T-shirt and slippers, as we have rarely seen him on TV.

Mariota is scheduled to lead off the sixth year at 1 p.m. on ESPN2 (replays will run to the April 30 draft) with subsequent sessions to feature Jameis Winston, Bryce Petty, Brett Hundley and Garrett Grayson.

Gruden diagrams a play borrowed from his 2012 session with Stanford’s Andrew Luck, the "spider 2 Y Banana Z Over" and then asks Mariota to run it on the practice field.

Then he chides Mariota, who operated sans huddle at Oregon, taking only five plays from under center in 2014. "Break the huddle, please!" Gruden yells. "Get ’em out of the huddle Marry-ota," before exclaiming, "Good, good, good."

Gruden takes shots at Oregon’s uniforms, zeroing in on a video clip of the Michigan State game and telling Mariota, "That might have been the worst ensemble in the history of Oregon. I worried about you guys, four grown men, wearing all yellow, holding hands … you’ve got your yellow uniforms, your yellow socks, your yellow face masks and you’re getting smashed like bananas (by Michigan State)."

Re-running video of a sack of Mariota, Gruden said, "Look at you. I loved it. I started rooting against you just because you wore those uniforms."

At another point, Gruden asks Mariota, "How do you stay so calm all the time, man? Does anything irritate you?"

To which Mariota replies, "Nah … losing does."

Whereupon Gruden begins to tap his fingers on the desk in an attempt to annoy, asking, "Does it bother you?"

Mariota shoots back, "Does it bother you?"

To which Gruden replies, tongue-in-cheek, "You’re starting to bother me."

Reach Ferd Lewis at flewis@staradvertiser.com or 529-4820.