BATON ROUGE, La. -- Just 13 weeks removed from surgery to repair a torn ACL, LSU quarterback Zach Mettenberger impressed a packed house full of NFL coaches, general managers and scouts by going through a full pro day workout on Wednesday.

By most accounts, Mettenberger helped to boost his draft stock with a display that would have been considered solid even if had never been injured. He's projected as a possible second- or third-round draft choice.

"It says a lot about him. And his doctor," said New Orleans Saints coach Sean Payton, who was one of five NFL coaches in attendance for LSU's talent-rich pro day. "It's pretty impressive. You know, 10 years ago you couldn't do that. I thought he did a real good job."

Mettenberger, who had surgery on Jan. 2 to repair his left knee, threw nearly 125 passes and made every throw while wearing a helmet and shoulder pads -- the new trend started by fellow prospect Johnny Manziel last month.

The 6-foot-5, 224-pounder moved in the pocket and threw on the run at times. And he consistently showed off a big arm that many analysts consider to be among the strongest of this year's draft prospects.

Naturally, Mettenberger showed some signs of fatigue with a few mistimed throws. But observers said he threw even more balls than quarterbacks usually do. And his arm strength remained intact through the workout.

"I thought he did outstanding. Almost miraculous," said LSU offensive coordinator Cam Cameron, the longtime former NFL coach who directed the workout. "Thirteen weeks after surgery, to come out here and throw more than a hundred balls and complete 90-plus percent of them. ...

"He was grinding today. We could have come out, made it a nice, easy workout, 50 balls. I've been to a couple of these, guys threw 40 balls and called it a day. But I think arm strength matters, and I think arm endurance matters."

Mettenberger was a little harder on himself, saying, "I wasn't too pleased with myself on some of those throws today. But sometimes I hold myself to an almost unrealistic standard. ... All things considered, I thought I did OK, but I still have a lot of room to improve on."

Mettenberger said he thinks Wednesday's workout will also encourage more NFL teams to invite him in for private workouts, since he had been told teams were hesitant to work him out because of the uncertainty over his health.

Mettenberger said his first visit is lined up for Thursday with the Jacksonville Jaguars, followed by a Saturday trip to visit the Detroit Lions.

"You know, I've been saying for a couple weeks now that I was healthy and good enough to go, and I don't think y'all believed me," Mettenberger said. "I think the biggest thing I wanted to do was show that I could go out there and take an explosive drop like everyone knows I can."

Mettenberger estimated that he is about 85 or 90 percent healthy and that he expects to be 100 percent in time for rookie camps in mid-May. LSU trainer Jack Marucci backed up that optimistic timetable by saying that Mettenberger's knee is already showing 95 to 97 percent strength on the Cybex machine that's used to test such injuries.

Mettenberger's surgery was performed by LSU team orthopedist Dr. Brent Bankston, who prefers to use a hamstring tendon instead of a patellar tendon. And Marucci said many LSU players in recent years have returned under similar timetables. Both procedures are common, with different surgeons having different preferences.

ESPN injury analyst Stephania Bell (who did not attend Wednesday's workout) said the type of work Mettenberger did Wednesday should certainly be considered a good sign. However, she cautioned that the knee is still going through the healing process and no one should consider his workout as a sign that he is now fully healed.

The bigger tests will come down the road when he is under duress -- either taking hits or escaping pressure, etc. It is possible that Mettenberger could be playing for a team in the preseason, though.

"I think I showed that I'm not gonna start the season on a PUP list," Mettenberger said. "I think I showed that I'm gonna be healthy enough to practice and compete for a job. And by the time the season rolls around, I'm gonna be fully healed, no question."

Mettenberger's injury came in the final regular-season game of his breakout senior year with the Tigers, in which he threw for 3,082 yards, 22 touchdowns and eight interceptions. Mettenberger's career got off to a bumpy start. First, there was an off-field arrest for misdemeanor sexual battery that led to his dismissal from the Georgia football team.

Then it took him a while to shine consistently at LSU. But he started to bloom under Cameron's tutelage in a pro-style offense last year. It's possible Mettenberger could rise up high into the second round of the draft, though opinions on the "second tier" of quarterbacks seem to be all over the map.

ESPN analyst Ron Jaworski, for one, said recently he thinks Mettenberger is the second-best quarterback prospect in this year's class behind only Central Florida's Blake Bortles.

Payton and other NFL talent evaluators consistently mentioned how much they enjoyed the workout that was put together by Cameron, who said he modeled it after a typical LSU practice session.

Receivers Odell Beckham Jr. and Jarvis Landry also appeared to strengthen their draft prospects. Beckham, a dynamic athlete who could crack the top 20 overall picks, shined during the passing drills. He didn't need to run the 40-yard dash since he had already posted a time of 4.43 seconds at the NFL scouting combine.

Landry, meanwhile, posted a badly-needed 40-yard dash time of 4.58 seconds, according to the school. Landry, a possible second-round pick, had run a surprisingly-slow time of 4.77 seconds at the combine.

Beckham said he has individual visits lined up with the New York Jets, Cincinnati Bengals and Buffalo Bills among other teams. He also had dinner with the Pittsburgh Steelers on Tuesday night and was planning to have dinner Wednesday night with members of the Saints' contingent, which always comes to LSU's pro day in full force since it's an hour away from New Orleans.

Other NFL coaches in attendance Wednesday were the New York Jets' Rex Ryan, Steelers' Mike Tomlin, the Philadelphia Eagles' Chip Kelly and the Minnesota Vikings' Mike Zimmer.