Trez is back.
The 6-foot-8 Harrell announced his decision via his Twitter account on Monday afternoon. He was projected as a late first-round pick in the draft and had until April 27 to make a decision.
"I will make the best decision for me," Harrell said recently.
Harrell, whose stock started to rise last summer on a USA Basketball team, puts the Cardinals back into the national title talk with his return for next season.
"This is obviously great news," U of L coach Rick Pitino said. "Like Gorgui Dieng, he will benefit tremendously from playing his junior season. We hope, like Russ Smith, that he can become a first-team All-America selection.
"Montrezl is a Louisville man and we're all very excited to have Montrezl as a co-captain with Wayne Blackshear."
As a sophomore, Harrell started all 37 games and averaged 14 points and 8.4 rebounds a game. He also was second on the team with 49 blocks.
Harrell set a new school record with 98 dunks on the season, which surpassed the old mark set by Chane Behanan and Pervis Ellison by 39 dunks.
Harrell hit 223 of 366 (60.9 percent) from the field to lead the team.
"I wouldn't say I had a great year," Harrell said. "I would say I had a solid year. I improved in a lot of areas and I think that's great and all, but none of that means anything when you lose early (in the tournament)."
Here's video of Harrell after the final game: