TCU is poised to be one of the top teams in the Big 12 this year, but lost a key defensive piece for the season on Wednesday. Defensive tackle Ross Blacklock is out for the season after suffering an Achilles injury in a non-contact drill during the Horned Frogs practice on Tuesday, according to the Associated Press.

Blacklock was a star as a freshman starting every game in 2017, and being counted on as one of the leaders in the trenches for Gary Patterson's crew heading into the 2018 season. He notched 27 tackles, 6.5 for loss and tallied two sacks last year; and was named the Big 12 co-defensive freshman of the year. The only other TCU player to earn the honor was Devonte Fields in 2012.

At 6-foot-4, 329 pounds, the Missouri City, Texas, native was being counted on to be one of the run stuffers in the middle of the defensive line. His emergence as a key piece last year helped TCU finish with the best run defense in the Big 12 (103.93 yards per game), best total defense (331.4 yards per game) and the most sacks in the conference with 42 -- 11 more than second place Texas.

Blacklock was a four-star prospect in the class of 2016 coming out of Elkins High School. 

TCU opens the 2018 season at home on Sept. 1 vs. Southern.