Arizona guard Allonzo Trier has been deemed ineligible by the NCAA after he tested positive for a banned substance in January, the school announced Thursday.

The NCAA reported there was a trace amount of a banned substance found in Trier's system, but it was enough for him to be deemed ineligible.

"Earlier today, the University of Arizona was notified that the NCAA has declared Allonzo Trier ineligible," the school said in a statement. "In late January 2018, Allonzo participated in an NCAA student-athlete drug screening. The results of that test, confirmed today, revealed the reappearance of a trace amount of a banned substance. The amount detected was miniscule by scientific standards and appears to be a remnant of a substance, which the NCAA agreed, Allonzo had unknowingly ingested in 2016. The University is appealing the decision and is hopeful that Allonzo will regain his eligibility soon."

Trier failed a drug test in 2016 and was ruled ineligible to return to the team until the substance was out of his system. After missing the first 19 games of last season he returned in time for the second half of the Wildcats' season and helped Arizona to an Elite 8 berth. 

The junior guard is second on the team in scoring, averaging 19.6 points per game on the season. Arizona is currently ranked No. 14 in the country with a 21-6 record.