The depth of Alabama's backfield took a big blow ahead of A-Day. Running back Ronnie Clark reportedly tore his Achilles tendon during the Crimson Tide's final practice of spring.

According to AL.com, Clark suffered the injury on Thursday, which is the second time it's happened in just two years on campus. The Calera native tore his other Achilles during his freshman season in 2014.

Clark had been getting carries behind Bo Scarbrough and Damien Harris this spring, but now the No. 3 running back is an unknown.

So who's left on the roster for A-Day? The remaining running backs are Lawrence Erekosima, Derrick Gore, Avery Reid, and Ty Turner. Gore, a junior, is the only player with any game experience.

Alabama will bring in two running backs this summer as part of the 2016 signing class. North Carolina four-star B.J. Emmons, an Under Armour All-American, might have the best chance to contribute early, but Joshua Jacobs earned a scholarship offer late in the process after a breakout senior season.

There is no timeframe on Clark's recovery, but there's no question that the Crimson Tide will rely heavily on Scarbrough and Harris.