No reason or length was given for the suspension, though Powell will be allowed to practice with the team.
Powell, a preseason first-team All-Southeastern Conference selection, is averaging 7.4 points this season while recovering from a broken foot. Last season, the sophomore averaged 14.9 points and 6.7.
Arkansas coach John Pelphrey said Monday that Powell was delayed in returning to school after the holiday break due to a car accident.
After Arkansas' 87-59 victory Wednesday, Pelphrey said he told Powell of the suspension the day before and that the forward handled the news "very well."
"I think it's a fluid timetable," Pelphrey said. "I think it can be as long as it needs to be and it can be as short as it needs to be."
After scoring a season-high 17 points in a win over Mississippi Valley State on Dec. 15, Powell played just 10 minutes in a loss to Texas A&M. He followed that by going scoreless in only one minute in Arkansas' 67-59 win over Texas Southern on Dec. 22.
"In the release, we talk about how committed he's been to doing certain things, things we find important," Pelphrey said. "I believe he will again.
"I think he wants to be out there with us, I really do."
Arkansas scoring leader Rotnei Clarke, who was suspended in the preseason, said he learned of Powell's suspension Wednesday.
"I know he'll definitely bounce back," Clarke said. "I could talk to him about it, just staying positive. Like I said, that's between him and Coach, but he'll bounce back. Whenever it's time for him to come back, he'll be ready to go and we'll welcome him with open arms. He's our teammate."