The Indianapolis Colts have gone from Super Bowl contenders to scrambling in a matter of less than a week, as franchise quarterback Andrew Luck announced his sudden retirement from the NFL last Saturday, pressing Jacoby Brissett into duty as the starter.

The Colts seem perfectly content with going into the season with Brissett under center, but now, Indianapolis needs a competent backup in case things with Brissett go south.

So, here are the three top (somewhat realistic) options for the Colts to back up Brissett.

3. Teddy Bridgewater

If it weren't for a devastating knee injury that occurred during the summer of 2016, Teddy Bridgewater would likely still be the starting quarterback of the Minnesota Vikings right now.

Instead, Bridgewater has turned into a journeyman of sorts, as he signed with the Jets in March 2018 before being traded to the New Orleans Saints later that offseason.

Teddy Bridgewater, Saints

The Saints then re-signed Bridgewater earlier this offseason, as they are clearly hoping he will be Drew Brees' successor once Brees decides to hang up his cleats.

But could New Orleans trade Bridgewater now in order to get some nice value in return?

It seems unlikely, as the Colts likely wouldn't surrender too much for a backup, and with Brees now 40 years old, I'm not sure it would be worth it for New Orleans to trade the 26-year-old Bridgewater, but if Indianapolis becomes desperate, it's definitely a move that makes sense for Indy.

Bridgewater isn't fantastic, but he has proven he is at least capable of being a starting quarterback in the NFL, and he is a tremendous locker room presence.

2. Nick Mullens

Nick Mullens stepped in for an injured Jimmy Garoppolo with the San Francisco 49ers last season and actually played fairly well, throwing for 2,277 yards, 13 touchdowns and 10 interceptions while completing 64.2 percent of his passes and posting a passer rating of 90.8 in eight starts.

Nick Mullens, 49ers

But now, Garoppolo is back, so Mullens will return to his backup role.

With San Francisco seeming very committed to Garoppolo for the future, it could consider trading Mullens, who is just 24 years old and is hardly making any money.

Should Brissett show he is not the quarterback of the future for the Colts, they could then turn to Mullens. who certainly showed promise during his time with the Niners in 2018.

But whether or not the 49ers would actually part with Mullens now with Garoppolo still being unproven is the question.

1. Case Keenum

That brings us to the most realistic name on this list: Case Keenum.

The Washington Redskins acquired Keenum earlier this offseason, originally intending to have him battle for the starting quarterback job with Colt McCoy, but then, Dwayne Haskins fell into the Redskins' laps during the draft.

Case Keenum, Redskins

As of right now, Keenum is Washington's starting quarterback, but obviously, Haskins is the guy for the future, and you have to think that at some point in 2019, Haskins will get some reps.

But the Redskins could still play out that strategy with McCoy instead of Keenum and get some value for Keenum in the process.

Keenum isn't a great quarterback by any stretch of the imagination, but he is probably a step above a guy like Ryan Fitzpatrick, as he led the Vikings to the NFC Championship Game a couple of years ago.

At worst, he is a very proficient backup who could help teach Brissett, and if Brissett struggles, then the Colts can feel comfortable inserting Keenum into the starting role.