Cincinnati Bengals rookie Rodney Anderson had been impressing his coaches this camp. There was even talk he might be able to give Joe Mixon a bit more rest once the regular season started. Then tragedy struck for the former Oklahoma Sooner running back.

In the final game of the NFL preseason, Anderson left the Bengals' contest against the Indianapolis Colts with an apparent knee injury. A game that was billed as simply a way for the backups to show what they can do, ended up being the last game of Anderson's season.

That is at least what preliminary reports are now saying.

NFL Network reporter Tom Pelissero reported on Friday morning the Cincinnati Bengals believe Anderson tore his ACL. The injury would be bad enough all on its own. The fact this isn't the first time he's torn his ACL makes it worse.

Is Bengals' rookie getting a rep?

It's never entirely fair when an athlete gets the reputation of being "injury prone" but that is exactly what is happening with Rodney Anderson. The rookie running back was activated by Cincinnati on August 7 after sitting out the last few months because ... of a torn ACL.

Anderson suffered that injury in just his second game of the season last year. It cost him his senior year at Oklahoma. The back has had several injuries in the very recent past.

He missed most of the 2016 season with a neck injury and sat out 2015 with an ankle injury.

When healthy, he's shown the flashes that led to the Cincinnati Bengals taking a flier on him. In 2017, his only full season at Oklahoma, he ran for 1,161 yards and 13 touchdowns (6.2 yards per carry). He also caught 17 passes for 281 yards and another five touchdowns.

Last year, he was off to a great start, carrying 11 times for 119 yards (10.8 YPC) and three touchdowns. He was off to a very good start with the Cincinnati Bengals as well. And now he'll have to try and start over. If there is one bright side, this injury was early enough that it's possible he could be back in time to contribute in 2020.

Of course, two tears to the same ACL could also mean he's completely done.

Rodney Anderson's story is going to be one to watch over the next few months.

Cincinnati Bengals going with three backs

Anderson's injury isn't just bad news for him. It also leaves the Cincinnati Bengals with a relatively thin depth chart at his position. At the moment, only Joe Mixon and Giovani Bernard are healthy and active.

The good news is that third-stringer Trayveon Williams is expected back from his injury by opening week. Still, should one of the top two go down, the franchise could be in trouble. For now, it appears the Cincinnati Bengals are going to wait and see if an injury does crop up before they attempt to add a fourth back to the stable.