Pregame talk about 14th-ranked Texas A&M's game against Vanderbilt has been about the health of the teams' starting quarterbacks, but the condition of the defenses might well be the deciding factor in the first meeting between the two Southeastern Conference schools.
A&M's Johnny Manziel injured his throwing shoulder on the first play of the fourth quarter in last week's 45-41 loss to Auburn. He returned and completed 9 of 10 passes.
Manziel wore a sling at Monday's practice as a precautionary measure, and head coach Kevin Sumlin said he would determine Manziel's status for Saturday's game based on what the sophomore could do in practice -- Sumlin calling Manziel's status "hopeful."
Vanderbilt coach James Franklin says he doesn't have to wait until Saturday's 11:21 a.m. start at Kyle Field to know who will be quarterbacking the Aggies (5-2, 2-2).
"Well, Manziel's playing," Franklin said during the Southeastern Conference coaches' teleconference Wednesday. "I don't think there's any doubt or question about that whatsoever."
After practice that same day, Franklin added that he expects Manziel "will be 135-percent healthy, if that's possible."
Franklin talked about Manziel jumping up, making a pass, running 80 yards, holding his knee, then avoiding seven defenders.
"He's going to be fine," Franklin said. "I think he's got like titanium bones."
Vanderbilt senior quarterback Austyn Carta-Samuels isn't as fortunate. He suffered an injury to his left knee and leg in last week's 31-27 victory over Georgia and will be replaced by redshirt freshman Patton Robinette.
Against Georgia, Robinette took over when Carta-Samuels left the game and threw for 107 yards to help the Commodores (4-3, 1-3) rally from a 13-point deficit.
"I think the fact that he played last week and the experience ... he's probably preparing a little different this week depending on how this situation plays out," Franklin said. "He shouldn't, but we all know that's human nature. I think that'll give him the opportunity to play better the next time he plays."
Robinette has big shoes to fill.
Carta-Samuels started two years at Wyoming before transferring to Vanderbilt, and he was coming into his own this season with 1,672 yards and 10 touchdowns passing with seven interceptions. He has completed 65.5 percent of his passes (129 of 197) and has a passing efficiency of 146.42, which ranks 34th nationally.
Robinette is more of a dual-threat quarterback, having rushed for 886 yards his senior season in high school with 16 TDs to be Tennessee's Gatorade Player of the Year. Mobile quarterbacks have given A&M problems. Last week, Auburn quarterback Nick Marshall rushed for 100 yards and two touchdowns and threw for 236 yards and two more TDs to earn SEC offensive player of the week honors.
"We need to get better on defense. There's no doubt about that," Sumlin said.
A&M's rankings in the four major defensive categories continue to slide -- No. 112 in rushing (226.6 yards per game), No. 103 in passing (267.9), No. 118 in total (494.4) and No. 104 in scoring (33.9 points per game).
The unit has been in transition all season because of suspensions, injuries and players failing to take advantage of their chances. The latest change came with the return of junior Floyd Raven Sr. to free safety last week, allowing Deshazor Everett to return to cornerback. Raven was suspended for the season opener, then missed three games with a collarbone injury but has worked himself back into the starting lineup with his play in the last two games.
True freshman linebacker Darian Claiborne will be making his fifth straight start and true freshman nose guard Isaiah Golden will be making his third straight since replacing senior Kirby Ennis, who suffered a season-ending knee injury.
"We've got what we have, and that's what we're going to go with," A&M defensive coordinator Mark Snyder said. "It's a matter of game reps, playing together, communicating together and those kind of things."
Big plays have killed A&M's defense all year, which was the case last week with three Auburn plays going for 152 yards.
"Those are the ones that got us, those explosives," Snyder said. "Vividly for me, the jailbreak for the [43-yard touchdown catch by Sammie Coates] was a backbreaker."
A&M also has allowed 21 points in the fourth quarter in each of the last two games.
"I don't have the answer to that question," Snyder said. "Are we getting worn down? That's something we're talking about as a defensive staff. That's not been our MO. Typically, we start really fast and our [starters come] out at halftime, and it's the younger guys playing. It hasn't been like that this year."
Vanderbilt's defense can relate.
The Commodores have been bashed for an average of 530.3 yards in losses to Missouri, South Carolina and Ole Miss. Most expected the same last week against Georgia, which came in averaging 36.3 points and 479.5 yards per game in SEC play.
But Vanderbilt played by far its best defensive game of the year, holding Georgia to a season-low 221 yards. The Bulldogs scored only a field goal in the second half as Vanderbilt rallied from a 27-14 deficit. Georgia senior quarterback Aaron Murray threw for only 114 yards on 16 of 28 passing.
"We played with fire," said senior linebacker Karl Butler, who returned from an injury. "I felt like the whole team played like that. The offense had our back, and the defense just came out and did what we were capable of doing."
Vanderbilt will be tested by A&M's high-powered offense that averages 588.7 yards and 46.9 points per game. Against Auburn, A&M sophomore wide receiver Mike Evans had a school-record 287 receiving yards and four touchdown catches, which tied the school record.
Vanderbilt also has one of the nation's top receivers in Jordan Matthews, who is coming off a career-high 11-catch game.
Vanderbilt is trying to build on the school's first back-to-back bowl seasons while A&M will be looking to return to the Top 10 after falling out of it for the first time in 11 months.