Nick Marshall returned to the sideline after about 10 minutes in the Auburn locker room and made his way over to Jeremy Johnson.

Looking up at the scoreboard, which showed No. 11 Auburn with a 38-point lead late in the second quarter, the junior starting quarterback seemed surprised.

“You already threw two touchdowns?” Marshall asked.

“Yeah,” Johnson answered.

“That’s good, just keep leading.”

It has been Marshall’s constant support and words of encouragement that have helped Johnson, Auburn’s talented freshman quarterback, fill in whenever called upon, especially Saturday.

Despite losing Marshall to an injury to his throwing shoulder two plays into the second quarter, the Tigers’ potent offense didn’t miss a beat with Johnson behind center as Auburn rolled up 628 yards of offense and blasted Florida Atlantic 45-10 on a chilly Saturday evening at Jordan-Hare Stadium.

“Coach (Gus) Malzahn always tells me to prepare as a starter, stay focused like a starter, so really that’s all I did throughout the week and throughout the game,” Johnson said. “So when I came in, I was able to execute.”

Johnson finished 10-of-16 passing for 192 yards, one interception and a pair of long touchdown passes to sophomore speedster Sammie Coates, who led the receivers with 113 yards on three catches.

The Tigers’ SEC-leading ground game kept churning out yards against Florida Atlantic, racking up 422 rushing yards despite no single 100-yard rusher for their second 400-plus game of the season. Ten different rushers registered a carry, including Cameron Artis-Payne, who led the team with 93 rushing yards, and Corey Grant, who added 75 yards on the ground.

Despite playing only 16 minutes, Marshall was Auburn’s third-leading rusher with 73 yards, and he led the team with 12.2 yards per carry. Marshall was also 1-for-1 passing when he converted a third-and-10 play to Marcus Davis on Auburn’s first pass of the game.

According to teammates, Marshall injured his throwing shoulder on the first play of Auburn’s third offensive series when he lowered it on a 9-yard run out of bounds to lay a hit on Florida Atlantic defensive back D’Joun Smith on the sideline.

“He hurt his shoulder the play way before that, so I kinda knew he was hurt and I was just asking was he all right,” Johnson said, “And once he got slung and I saw he went down, Coach just told me to start warming up — and that’s what I did.”

Despite staying in for 12 more offensive plays, including capping that third series with a 10-yard touchdown run to put Auburn (7-1, 3-1 SEC) ahead 21-0 with 6:54 left in the first quarter, Marshall got a little ribbing from teammates for the play.

“Yeah, I slapped his head for trying to be a tough guy,” Auburn defensive end Dee Ford said. “But it was all love. It’s football, it happens.

“I always pick on him because he’s a frail guy, and he was trying to run people over. At the end of the day you’re a quarterback.”

Marshall paced the Tigers’ offense from the opening kick as Auburn scored on its first three possessions, including an 8-yard touchdown run by Tre Mason and a 43-yard score by Grant one play after Jermaine Whitehead recovered a fumble caused by Ford on Florida Atlantic’s third offensive play.

Marshall left the field and never returned after he was sacked and spun to the ground, landing on his right shoulder, by Owls defensive end Robinson Eugene for an 8-yard loss two plays into the second quarter.

One play later, on third-and-13, Johnson unleashed a deep pass and found Coates for a 36-yard touchdown with 13:55 left. The pair hooked up again on the first play of Auburn’s eighth offensive series for 67 yards to put the Tigers ahead, 38-0, with 3:10 remaining in the second quarter.