Johnny Manziel

Rarely does a top 10 matchup center around one player so much. Here's what you need to know about the Aggies' Johnny Manziel

1. Johnny has made the full heel turn.

After sitting out the first half of A&M's season-opening win over Rice for signing autographs, Johnny Football entered the game and immediately began making autograph gestures at opposing defenders. He was later flagged for jawing with opponents and pulled from the game by head coach Kevin Sumlin.

Manziel's full embrace of his offseason problems and bad reputation has only drawn more ire from college football's old guard. Barry Switzer -- who coached Brian Bosworth -- said he wanted to "jerk his face mask and grab him." Former Notre Dame and South Carolina head coach Lou Holtz -- whose team got into a brawl with Clemson before his final game as a head coach -- said he would grab Manziel by the throat. Oklahoma defensive coordinator Mike Stoops -- who is no saint on the sideline -- wants to see him in jail. Charles Barkley -- who is Charles Barkley -- said Manziel's antics would force him to support Alabama for the first time in his life.

Manziel is unapologetically good. He rubs it in everyone's face. He even has a money-related signature gesture. He's a butler and a dollar-sign belt away from becoming college football's Ted DiBiase.2. Johnny's gonna run. Or at least he's gonna try.

Last year, Manziel's abilities to extend plays against Alabama's pass rush and turn losses into gains were crucial to the Aggies' victory over the Crimson Tide. Earlier this week, Alabama head coach Nick Saban was asked how he planned to counteract Manziel. Saban conceded his defensive line is going to have to contain Manziel more than pursue him:

Saban will do his best to make Manziel a pocket passer, especially given the relative youth and inexperience of A&M's receivers. Last season, it was easier said than done. Manziel ran for more than 90 yards in nine of last season's 13 games, including 229 yards against Oklahoma in the Cotton Bowl and 181 yards against Louisiana Tech. Alabama let Manziel run for 92 yards on 18 carries last season. But in games where Manziel was held to 60 yards or less, Texas A&M was 0-2.

Manziel has not run as effectively this season: 19 yards on six carries in a half against Rice, and 36 yards on seven rushes last week against Sam Houston State. But expect the return of scramblin' Johnny Manziel Saturday, and Alabama's ability to contain him could determine the outcome.3. Saturday will determine whether he can win his second Heisman Trophy.
Manziel's numbers throughout 2012 were impressive, but make no mistake: Johnny Football won his Heisman Trophy with his performance against Alabama. He had been good to that point, but his 24/31, 253-yard performance, his rushing totals and that signature high-profile play that every Heisman winner needs, won him college football's most prestigious award: Johnny isn't sneaking up on anyone this season, and he still has games against LSU and Ole Miss on the schedule, but he likely won't face a defense of the same caliber as Alabama. He won't have the same hype surrounding a game as he does today. And he won't have an opponent so hell-bent on stopping him as this week's visitors. A good game today keeps him in the running -- it could make him the frontrunner -- but if Johnny Football struggles today and Texas A&M loses, stodgy Heisman voters already inclined to dislike him for his antics will sieze on his difficulties and look elsewhere.