Those two Crimson Tide stars instead finished their 'Bama careers with a 45-31 loss to Oklahoma in the Sugar Bowl on Thursday night.
Two losses in three years, and two more in the last five weeks. It was a tough way to go for Alabama (11-2) after two straight national titles, and an utterly uncharacteristic performance both for the defense and McCarron.
"I think when you have the kind of success that we have had here in the past, it doesn't happen by accident," Tide coach Nick Saban said. "I think it takes a lot of hard work, and I think a lot of people have to buy into doing things at a very high standard, which these seniors and a lot of former players have set.
"And we certainly didn't play maybe up to that standard."
Then again, no program in the country set a higher standard than the Tide. Even without McCarron, the Heisman Trophy runner-up, and Butkus Award-winning Mosley, Saban and Alabama could very well be in Southeastern Conference and national title contention again next season.
It's what happened after the Tide's last two-game losing streak ended the 2008 season, including coincidentally a two-touchdown loss in the Sugar Bowl, that time to Utah. Alabama responded with an unbeaten 2009 en route to the first of three national titles in four years.
There's no shortage of talent for a program likely poised to pull in another top-rated recruiting class, including six returning quarterbacks. Only Blake Sims has thrown a pass for the Tide, going 18 of 29 for 167 yards and two touchdowns.
Alabama must replace seven senior starters, including cornerback Deion Belue, guard Anthony Steen and No. 2 receiver Kevin Norwood.
The Tide could lose several underclassmen to the NFL draft, too. That includes All-America left tackle Cyrus Kouandjio and All-Southeastern Conference safety HaHa Clinton-Dix, both regarded as likely first-round picks.
McCarron had gone 36-2 before Alabama lost to Auburn on the last play of the regular season and fell to the Sooners.
He passed for a career-high 387 yards and two touchdowns, but his two interceptions set up Oklahoma TDs, and his fumble was returned for a score in the final minute. It was an ignominious ending for a player regarded as one of the Tide's best quarterbacks, and McCarron was hard on himself.
"It's football. It happens," he said. "I wish it wouldn't have happened, but I'll definitely take the loss and definitely take the blame, because a lot of it is probably my fault."
Whoever replaces him will be surrounded by a wealth of skill players. Five of the top six receivers return, led by Amari Cooper and tight end O.J. Howard. Tailback T.J. Yeldon is back after rushing for 1,245 yards and 14 touchdowns, along with backup Kenyan Drake.
Freshman Derrick Henry also turned in a huge game in the Sugar Bowl. He had eight carries for 100 yards, including a 43-yard touchdown. He took his first career catch 61 yards for a touchdown to cut Alabama's deficit to 38-31 with 6:22 remaining.
"Derrick had a really good bowl practice," Saban said. "Actually we decided that he was our second-best back going into this game, and we were going to give him an opportunity based on his performance in practice and what he had done and the confidence that he had gained throughout the course of the season in terms of knowing what to do and playing fast.
"And certainly had an outstanding game and did a really good job for us, and I think he has a bright future."
Defensively, safety Landon Collins, linebacker Trey DePriest and defensive end A'Shawn Robinson are set to return.
DePriest is eligible for the draft but has said he'll be back for his senior season.
Saban said the Sugar Bowl performance wasn't a hangover from the Iron Bowl defeat.
"I can't blame it on that," he said. "I thought our team late in the season from the LSU game on maybe didn't have the focus we needed to have. We didn't pay attention to detail, didn't do little things right, didn't practice well. I think that eventually caught up with us in the Auburn game."