And faring well in practice, where he's benefiting from going head to head against Gerald McCoy, the Bucs' three-time Pro Bowl defensive tackle.
''If you can block him you're going to be able to block a lot of other guys in the league, so it's awesome having a guy like him against you every play,'' said Marpet, who made history when he was drafted No. 61 overall out of tiny Hobart College, becoming the highest pick ever from a Division III program.
The 6-foot-4, 307-pound native of Hastings-on-Hudson, New York, was the Liberty League co-offensive player of the year last season. He impressed pro scouts with a solid performance against a higher level of competition at the Senior Bowl, and then bolstered his rising stock with a strong showing at the scouting combine.
Marpet played tackle in college, but the Bucs drafted him with intentions playing him at guard.
And the team's not concerned about the prospect of having two rookies on an offensive line responsible for protecting Winston, the 2013 Heisman Trophy-winning quarterback selected No. 1 overall.
Marpet, who's competing with two other young players to be the starter at right guard, lined up with the second-team offense for the first four days of camp.
''We're bringing them along and they are coming along fairly quick,'' coach Lovie Smith said, noting both second-round draft picks have progressed daily.
''The biggest difference ... is the quickness,'' Marpet said. ''The strength I've been able to handle, but everything is so quick, the whole game. It's just a lot faster.''
Working against McCoy in practice will only help the 22-year-old, Smith added.
''For Ali, there is no better place for him. I mean, Gerald McCoy is on the other side. He's having to get up to pace pretty quick. ... I'm pleased where he is,'' the coach said.
''I know moving forward we're still going to be rotating at right guard, and I know the position is up for grabs,'' the rookie added. ''But it was a smooth transition to start with the 2s and then finally getting reps with the 1s. And again, I still have a lot of things to work on.''
McCoy, entering his sixth season, said Marpet has the tools necessary to be a good lineman. All he lacks is the experience that'll provide the know-how and confidence to be effective.
''I think he has all the makings to be a really good guard in this league,'' McCoy said. ''Obviously he's made some rookie mistakes, but that's to be expected.''
Marpet appreciates the opportunity to learn from one of the league's elite defensive tackles.
''It is pretty huge. He gets me a whole lot, but knowing that I can get him if I am technically sound is huge for me,'' the rookie said, adding that McCoy has also helped him make adjustments.
''He corrects some things. There are a lot of things technically that I need to clean up,'' Marpet said. ''Sometimes my base gets a little wide, and he's told me to shorten that up a little bit. He's been encouraging, and even though we're competing, he's still helping me out, which is awesome to have.''
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