Marra felt a pop in his knee and had to be carried off the court in Louisville's 68-48 win over Lamar on Sunday night at the Global Sports Invitational. He originally was diagnosed with a left knee sprain, but a magnetic resonance imaging test at Jewish Hospital revealed the damage to the ACL, an injury that will force Marra to have surgery and miss up to 12 months with rehabilitation and recovery.
Marra, a consistent role player for coach Rick Pitino's surprisingly successful ensemble group, averaged 6.4 points in 20.4 minutes per game last season. The Cardinals (No. 8 ESPN/USA Today, No. 7 AP) are expected to further improve this season, but Pitino currently is battling the injury bug.
In addition to Marra, guard Peyton Siva spent time recovering from a concussion, forwards Stephan Van Treese and Rakeem Buckles are missing games with knee injuries and highly touted freshman recruit Wayne Blackshear required surgery on his shoulder and could miss much of the season as it heals.
The Cardinals face Butler at Hinkle Fieldhouse in Indianapolis on Saturday.
Eamonn Brennan covers men's college basketball for ESPN.com.