Hasley, a former walk-on from Aledo, Texas was a key contributor in the Frogs' inaugural season in the Big 12; starting ten games. Hasley finished second on the team in tackles with 79 (45 solo, 34 assists) and second in tackles for losses with 8.5.
Hasley's best game in 2012 was on the road at Kansas when he recorded a career-high 12 tackles and 2 sacks. For his performance Hasley was named Big 12 Defensive Player of the Week. He was also named by the Associate Press to the honorable-mention Big 12 team.
TCU started fall practices last Thursday and Hasley was expected to retain his starting position alongside Marcus Mallet.
Frogs head coach Gary Patterson thanked the former walk-on for his contributions to TCU's football team.
"I'd like to thank Joel for everything he's done for TCU and his commitment to our program," TCU head coach Gary Patterson said. "Joel is very close to completing his second degree at TCU, and he decided it was time to move on from football. We will miss him and wish him the best."
The linebacker unit was already light in numbers with only three scholarship returners from last year's squad. Juniors Paul Dawson and Jonathan Anderson are expected to compete for the void left by Hasley as well as two true freshmen; Sammy Douglas and Paul Whitmill. Patterson has given high praise to his freshmen backers in recent practice updates.
Hasley has already received his communication studies degree and will complete a second degree in geology later this year.