Former professional football player Pat Tillman was killed in Afghanistan in April 2004. (AP Photo/Photography Plus via Williamson Stealth Media Solutions)

CORRECTED 4/15/11, 6:37 a.m.: Earlier versions of this post mistakenly said McChrystal had admitted to being part of a coverup related to the Tillman investigation. The former commander of U.S. operations in Afghanistan admitted "mistakes" relating to the Tillman probe.

The mother of former professional football player Pat Tillman is calling for the removal of Gen. Stanley McChrystal from his recent appointment by the White House as co-chair of a commission on military families, ABC News reports.

Mary Tillman, whose son left his NFL career to become an Army Ranger and was killed in Afghanistan by friendly fire in April 2004, said McChrystal — the commander of special operations in Afghanistan at the time — was involved in the coverup of the circumstances surrounding Pat Tillman’s death and said President Obama’s appointment of the now-retired general “makes him look foolish.”

I was actually pretty shocked to hear it; I don't think it’s the appropriate choice,” Tillman told ABC News. “Considering that we have plenty of evidence indicating that McChrystal was involved in the cover-up of Pat’s death. . .he's not the right person for that kind of a job.”

Shortly after Tillman’s death in 2004, the ex-Arizona Cardinal was awarded the Silver Star for bravery. The Army’s initial report did not include any mention that Tillman was killed by friendly fire and misrepresented key facts of the incident, internal documents showed.

In 2009, McChrystal admitted to “mistakes” related to the Tillman investigation, including failing to review the Silver Star recommendation adequately, and apologized. Last year, McChrystal was dismissed as commander of U.S. forces in Afghanistan after an article in Rolling Stone quoted the general and members of his staff disparaging senior Obama administration officials.