Despite being considered a top running back prospect for the 2012 NFL draft, he went undrafted due to concerns over a potentially degenerative shoulder condition.

Rated the #4 all-purpose back in the nation, Polk led his team to a 12-1 record and to the Inland Division semifinals in 2007.

Polk earned first-team All-CIF Southern Section Inland Division honors as well as being named a SuperPrep All-American his senior season.

[4] Polk's 284 yards was second-most in school history, trailing Hugh McElhenny's 296 in the 1950 Apple Cup.

Polk suffered a knee injury during practice before the 2011 season that needed to be corrected with arthroscopic surgery.

He finished fifth on the team in rushing yards (98), behind LeSean McCoy, Bryce Brown, Michael Vick and Nick Foles.

Due to injuries limiting the starter Arian Foster to only 4 games, Polk had more opportunities as the Texans' backup running back.