A Texas spokesperson confirmed to ESPN.com that Harrison has been cleared to practice and will rejoin the team for practice on Tuesday.
The decision comes one day after multiple reports that BYU denied an appeal of its decision to invalidate a credit Harrison received for an independent online study course from the school. Despite Harrison's return to practice, that matter remains unresolved.
Harrison used the three-hour credit to finish his associate's degree at Contra Costa College, and it had been validated both by his junior college and the University of Texas. BYU has since rejected the credit due to its policy that student-athletes attending schools other than BYU are not permitted to take its independent study courses.
Harrison is currently enrolled in summer classes at Texas, and he hadn't been permitted to practice with the Longhorns since Aug. 5 due to the eligibility issue. Per NCAA rules, he'll need to participate in three practice sessions before working out in full pads.
BYU spokesperson Carri Jenkins told ESPN.com on Monday that the school ended its review process last week but declined to share what decision was sent to Texas.
"We have completed our review, and a decision in regard to that review was sent to Mr. Harrison," Jenkins said. "It was sent via certified mail and issued Thursday of last week. Because of privacy guidelines, you need to contact Mr. Harrison regarding our decision."
The 6-foot-8, 310-pound junior was expected to become Texas' starting left tackle this season after joining the program in July. He participated in the Longhorns' first fall practice but had been held out ever since. Texas coach Mack Brown cited an "academic issue" but declined to comment further last week.
"I think it is a waiting game," Brown said. "Since it is an academic situation, I can't comment on it. They're just going through a process."
Texas coaches and players have said they are preparing for the season under the assumption that Harrison will not be available.
Texas had considered the issue a matter between BYU and Contra Costa College, but the likely next step will be appealing to the NCAA. In doing so, Texas might assert that other schools have taken advantage of the BYU program to maintain their student-athletes' eligibility.
Jenkins said it has been BYU's policy since 2006 that non-BYU student-athletes are not permitted to take the school's independent study courses.
"Based on an internal review out of a reevaluation our independent study program, we determined that to uphold the integrity of our program, we would exclude college athletes," Jenkins said.
Students who enroll for the courses, she said, are asked to certify that they read and understand that policy.
The policy states: "College athletes from schools other than BYU are not allowed to enroll in BYU Independent Study university-level courses. This restriction applies to students who are currently eligible as well as those seeking eligibility to participate in any collegiate athletic program."
According to a source, Contra Costa will remain firm in its stance that it will not revoke the associate's degree Harrison earned. A California state law prohibits the community college from changing Harrison's grade in the course "in the absence of mistake, fraud, bad faith, or incompetency."
Jenkins declined to say what initiated BYU's review of Harrison and his independent study course.
"If we are made (aware) of these situations, we take appropriate action after a thorough review," she said.
Multiple calls made to Contra Costa officials and football coach Alonzo Carter were not returned.
No. 15 Texas plays its second game of the season at BYU on Sept. 7.