Junior guard Joshua Langford was seen still wearing a boot during pre-game warm-ups as the No. 6 Spartans prepared to take on No. 13 Maryland.
Ahrens (6.1 PPG) hasn't been able to go in either of MSU's last two games, due to a back injury.
The Spartans (16-2, 7-0 Big Ten) have been getting along just fine without Langford, having won all five games he's sat out. MSU will try to earn its 12th straight win Monday night.
The Terrapins (16-3, 7-1) look to be the Big Ten's biggest challenger, behind Michigan State and rival Michigan. The Terps, winners of seven straight, are led by junior guard Anthony Cowan Jr. (17.9 PPG), who put up 26 points against the Spartans last season in East Lansing.
After Monday's showdown for first place in the conference, MSU heads to Iowa to take on the No. 19 Hawkeyes on Thursday, before heading to Purdue on Sunday to cap off a tough three-game week.