Too much partying, too little good judgment. He became sort of a gridiron version of Lindsay Lohan.
When you apparently get tossed from your job as a counselor at the Manning Passing Academy by Papa Manning himself, well, NFL personnel people will stand up and take notice.
Many of them suggested that Manziel's Quarterback Behaving Badly act last year had caused irreparable harm to his draft stock. But then he went out and threw for 37 touchdowns and 4,114 yards and ran for nine and 759, and put on a Superman-like performance in the Aggies' 52-48 win over Duke in the Chick-fil-A Bowl, and all was forgiven.
Well, maybe not all, but a lot. Boys will be boys, right?
When the first round of the NFL draft is held on May 8, Manziel is expected to be a top-10 pick, maybe even top five, maybe just maybe even top-one if he can convince the Houston Texans that he, and not Louisville's Teddy Bridgewater or Central Florida's Blake Bortles, is the quarterback of their dreams.
Manziel, Bridgewater and Bortles are the three top-rated quarterbacks in this year's draft. With five of the top eight teams in the draft desperately needing quarterback help, all three are expected to have very short stays in the green room at Radio City Music Hall.
At this point, the order they will come off the board remains anyone's guess. Ask three scouts or draft analysts to rank them and you'll get three different answers.
The NFL Network's Mike Mayock, who has as good an eye for quarterbacks as anyone I've ever met, has Bridgewater first, Manziel second and Bortles third.
ESPN's Mel Kiper also has Bridgewater first, but Bortles second and Manziel third. An NFC player personnel executive I spoke with ranked them Manziel-Bortles-Bridgewater.
There are questions about all three.
"None of these guys are Andrew Luck," Mayock said. "None of these guys are Peyton Manning. None of these guys, you sit there and say, 'It's a slam dunk. This is an easy one.' "
The Texans, who own the first pick, need a quarterback. They've pretty much thrown in the towel on West Chester's Matt Schaub, and they know they won't make it to the Super Bowl with Case Keenum or T.J. Yates behind center.
What they have to determine by May 8 is whether Manziel, Bridgewater or Bortles is the answer to their problems.
The public sentiment in Houston clearly is for Manziel, who is Texas-born and -bred and played his college ball only 90 miles from Reliant Stadium. The Texans can't make this decision based on public sentiment, though.
"It really comes down to whether ownership gets involved," Mayock said. "A - they have to believe in one of these three kids. And B - they have to say, 'Forget the whole local attraction thing.' The most important thing is to build for the future and win football games. That will take care of itself as long as you're winning games."
Texans general manager Rick Smith said yesterday at the NFL Scouting Combine that public sentiment will not factor into their decision.
"Our owner [Robert McNair] will not put that kind of pressure on us to respond that way," he said.
Manziel is an exciting player with a strong arm and Russell Wilson-like mobility. But he was measured at only 5-11 3/4 yesterday at the combine.
"The kid makes throws [and] he allows his receivers to make plays," Mayock said. "He extends plays. I watched the Alabama tape and he was like a combination of Fran Tarkenton and Doug Flutie. But then I watched the LSU and Missouri tapes, neither of which were really good tapes."
What Mayock saw in those two games was a quarterback who got claustrophobia in the pocket. Think Michael Vick in the 2004 NFC Championship Game against the Eagles when he was with the Falcons.
"I felt like he got frustrated in the pocket, and LSU and Missouri did a great job of controlling their rush and keeping him in the pocket," Mayock said. "And the more he was in the pocket, the more frustrated he got. He started to lose his accuracy. He started trying to escape the pocket way before he needed to.
"He likes those open spaces, and you've got to evaluate him a little differently because of that. Having said that, I do believe he's got the arm strength, athletic ability, the passion for the game. I believe in the kid. But you're going to have to live with some of those negative plays in addition to the positive ones."
Manziel bristled yesterday at suggestions that he can't play in the pocket.
"I'm looking forward to shutting up all of the people that are saying I'm just an improviser," he said.
"There's times where plays aren't going to go as scripted, as people draw them up on the white board. Whenever that happens and you go through your reads and you do certain things, there are going to be times when you need to take off and get outside the pocket and extend plays.
"At the same time, I want to be a guy who can drop back and go through my progressions, go through my reads and really take what's given to me by the defense."
Bortles, who, like Manziel, is an underclassman, wasn't on most scouts' radar last summer. But he had an outstanding junior season, throwing 25 touchdown passes and only nine interceptions. At 6-5 and 232 pounds, he's the biggest of the three quarterbacks, but also can run.
Bill O'Brien, the Texans' new head coach, got a firsthand look at Bortles last September when he carved up O'Brien's Penn State defense in a 34-31 Nittany Lions loss, completing 20 of 27 passes for 288 yards and three touchdowns.
"He played well," O'Brien said. "I thought he threw the ball well. He's a big guy. He's athletic. He's a competitive guy. It's been fun to watch him on tape, and it'll be good to watch him here [at the combine]."
Bridgewater is the most NFL-ready of the three quarterbacks. He played both under center and in the shotgun at Louisville. He had to read the entire field and make all of the throws.
"You can put the tape in and watch him do things and say, 'Yeah, that translates to the next level," Mayock said. "He's not as much a wild card as Manziel, and I think he's more developed in his reads and throws than Bortles."
None of the three is a sure thing, though.
"The more tape I watch of all three the more questions I have," Mayock said. "I don't want to overanalyze these guys, because there's a danger in that, also. But I just pick apart all three of them. I could not pick apart Andrew Luck.
"Obviously, Manziel is a different kind of evaluation and you have to buy in and embrace what he does. I think you're going to have to teach him, and he's got to be open and listening and learning. But he's a completely different evaluation and your team is going to have to change how they play and embrace his style.
"Bridgewater and Bortles, I think can both be good quarterbacks. But I'm not ready to say either of them is an All-Pro quarterback."
On Twitter: @Pdomo