The University of Maryland hired sports medicine consulting group Walters Incorporated to review what led to the death of Maryland football offensive lineman Jordan McNair, university spokeswoman Katie Lawson said.

Additionally, all football team workouts since McNair's death have been voluntary and will remain so until further notice, Lawson said.

Following a team conditioning test May 29, McNair was taken to the R Adams Cowley Shock Trauma Center in Baltimore, where he died June 13. While no cause of death has been announced, a GoFundMe page for his family said he received a liver transplant while hospitalized.

The investigation will begin by the end of the week, Lawson said. It could last to up to 90 days.

According to its website, Walters Incorporated is headed by Dr. Rod Walters, who has led the training staffs of Appalachian State and South Carolina and was inducted into the National Athletic Trainers Association Hall of Fame in 2005.

At a press conference the day after McNair's death, acting athletic director Damon Evans said the department would conduct an external review, but declined to say who would be carrying it out.

"The review will evaluate relevant policies and protocols," Lawson said. "The safety and well-being of our student-athletes is the highest priority."

During an organized team workout May 29, trainers noticed McNair was struggling to recover after completing 10 110-yard runs, which Evans called a "basic conditioning test." McNair was subsequently moved indoors and 911 was called, Evans said.

The team has informed its players that "regularly scheduled practices are voluntary until further notice," Lawson said.

"First and foremost the focus is on the well-being of the student-athletes," Lawson said. "This time is for them to grieve. We will continue to provide the resources our student-athletes need, which includes counseling services and access to spiritual leaders, during this difficult time.