Well, he did at first. Ultimately, though, Adams led the Commodores to the end zone twice and rallied them to a surprising 14-13 victory over Auburn.
"I got a lot of reps in practice this week," Adams said. "I felt I was real familiar with the game plan. When I got thrown in there, I felt pretty confident in the plays they were going to call."
Vanderbilt coach Bobby Johnson said he was confident in Adams, who started a few games last season when starter Chris Nickson was injured.
"Mackenzi is always ready to go," Johnson said. "He's a competitor. He wants to get in the game. And when he gets a chance, he wants to make things happen."
Vanderbilt probably wouldn't have won had Adams not gotten into the game. Nickson was 3-for-8 for 4 yards in 1½ quarters of play. He also threw a poor pass that was intercepted and set up a touchdown that staked Auburn to an early 13-0 lead.
In fact, the only offensive success Vanderbilt managed was when Nickson scrambled for 20 yards and later picked up 17 on a quarterback draw. But Johnson knew that wasn't likely to continue against Auburn's rugged defense.
"We had to throw the ball for sure," Johnson said. "That allows you to run a little better with the quarterback and quick sweeps. If they make you one-dimensional, you're in trouble."
In the second quarter, Nickson re-aggravated a shoulder injury; he had separated his right (throwing) two weeks before in a win over Ole Miss. Nickson exited, Adams entered and no one worried.
"Chris is great, but I don't think anyone was worried," Vanderbilt linebackerPatrick Benoist said. "We've always known what Mackenzi could do. Coming into the season, (he and Nickson) were neck and neck. I know I was never worried."
Auburn should've been.
After an exchange of punts and a 25-yard return by D.J. Moore set up the Commodores at Auburn's 30 with 3:30 left in the first half, Adams completed passes for 11, 12 and 3 yards to set up a first-and-goal situation. Then, after losing 10 yards on a sack, he threw a laser to Justin Wheeler for a 15-yard touchdown just 39 seconds before halftime.
Adams continued that momentum in the second half. He led two drives that ended with failed field-goal attempts, but on another he completed passes of 13, 18 and 9 yards and ran for 3 as the Commodores reached Auburn's 1.
From there, he rolled out right and was under pressure when he threw a pass to 6-foot-5 tight end Brandon Barden, who was surrounded by three defenders in the back of the end zone. Although it proved to be game-winning score, quarterback coach Jimmy Kiser wasn't pleased.
"Coach Kiser wasn't too happy on the phone," Adams said. "It was dangerous. Everything (on the play) was going to the right and he went left, so I tried to throw it high where only he could get it.
"He made a good play on the ball. It helps when you have guys that can help you out."
Adams finished 13 of 23 for 153 yards and two touchdowns. He also ran for 54 yards.
"He did good," Auburn coach Tommy Tuberville said. "He threw the ball well. They hit us on deep crossing routes. His sprinting out was a big key to the game. He threw it on the money on the run."
The victory enabled Vanderbilt (5-0 overall, 3-0 in the SEC) to remain in first place in the SEC East. If the Commodores can post a victory over Mississippi State this Saturday, they will remain in the lead and become eligible for their first bowl appearance since 1982.
There has been no word on whether Nickson's injured shoulder would prevent him from playing. But Adams showed he will be ready when he's asked to start a game – or a rally.
Olin Buchanan is the senior college football writer for Rivals.com. He can be reached at firstname.lastname@example.org.