ATLANTA (AP) -- Texas A&M coach Kevin Sumlin says Johnny Manziel surprised observers with his quiet demeanor this season following a series of offseason distractions.
Sumlin said proof of Manziel's growth also came on the field as he led No. 20 Texas A&M to a spot in Tuesday night's Chick-fil-A Bowl against No. 22 Duke.
The bowl game could be Manziel's college farewell. Many expect the third-year sophomore to enter the NFL draft, though he said this week he is ''nowhere close'' to a decision.
Manziel's every move was analyzed in his offseason following his Heisman Trophy-winning freshman season. He was tossed from a fraternity party, overslept at the Manning Passing Academy and was the target of an NCAA probe to determine if he signed autographs for money.
All the off-field noise ended with the start of the 2013 season. Manziel served a half-game suspension to close the NCAA issue and then went to work.
''We went through the year and I think people were shocked that he's kind of quiet,'' Sumlin said Monday. ''You've got the offseason part and then we've got the football season. I think he was extremely focused this year.''
Sumlin said Manziel also showed more maturity in his performance.
''I think he moved from an athlete that was playing quarterback to a quarterback that's an athlete,'' Sumlin said. ''I think he's improved as a passer, improved in his knowledge of not only what we're doing, but his knowledge of defenses, and I think that shows.''
Manziel led the Southeastern Conference with his 69.1 completion percentage and 311 yards passing per game. He is the player to watch as Texas A&M (8-4) tries for bowl wins in three straight seasons for the first time in school history. Duke (10-3) will try for its first bowl win since 1961.
''He's an outstanding quarterback,'' Duke coach David Cutcliffe said Monday. ''He's not just an athlete. He beats you in a lot of different ways. Certainly he's got a great receiving corps. His ability to create plays is second to none. In my lengthy career I really haven't seen a player that creates and ad-libs as well. It's certainly in part to his athleticism. But there is coaching involved in that.''
Here are five things to know about the Chick-fil-A Bowl:
SUSPENSIONS: Duke is without running back Jela Duncan, who was suspended this month for an undisclosed violation of its academic policy. Duncan led the Blue Devils with 562 yards rushing, and the suspension will carry through the 2014 season.
Texas A&M freshman linebacker Darian Claiborne, who is tied for the team lead with 89 tackles, was suspended this month following his arrest on two drug possession charges.
FOURTH QUARTER IS DUKE'S TIME: Duke outscored opponents 120-44 in the fourth quarter. The Blue Devils' defense allowed only one touchdown and three field goals in the fourth quarter during the team's eight-game winning streak.
STAFF SHUFFLING: Texas A&M secondary coach Marcel Yates is leaving the school following the game to become defensive coordinator at Boise State. Meanwhile, Duke offensive coordinator Kurt Roper is coaching his final game with the Blue Devils. Roper has accepted an offer to become offensive coordinator and quarterbacks coach at Florida. Roper also was an assistant head coach with the Blue Devils.
NO MIDDLE MAN: Texas A&M offensive coordinator Jake Spavital will call plays in place of running backs coach Clarence McKinney. In the past, plays were relayed from the press box to Spavital on the field, and Spavital then sent the play to Manziel. The change possibly allows the Aggies to move more up-tempo. Manziel said he hopes the offense can ''get in more of a rhythm ... and get our tempo where we want to. So I think coming in directly from the sideline will speed that up a little bit.''
MANY HAPPY RETURNS: Special teams could make a difference for Duke. Devon Edwards has returned two kickoffs for touchdowns. Jamison Crowder has returned two punts for touchdowns.