Jerome Harrison’s failed trade to Philadelphia may end up saving his life. (Hannah Foslien/Getty Images)

Update (1:20 p.m.): The Detroit Lions have placed running back Jerome Harrison on the reserve/non-football illness list one day after reports surfaced that he failed a physical due to the discovery of a brain tumor, according to the Detroit Free Press.

Detroit Lions running back Jerome Harrison failed his physical with the Philadelphia Eagles on Wednesday, voiding the trade that would have sent running back Ronnie Brown to the Lions.

For a player that had not been listed on his team’s injury report to fail a mid-season physical was curious — but now the reason is clear.

ESPN’s Adam Schefter reported that Eagles team doctors discovered a brain tumor when they examined Harrison to complete the trade process.

Without trade, Jerome Harrison doesn’t get physical. Without physical, doctors don’t find brain tumor. Trade might have saved his life.Thu Oct 20 16:50:57 via WhoSayAdam Schefter

The 28-year-old Harrison missed practice on Thursday and was listed with an “illness” on the team’s injury report. Detroit coach Jim Schwartz declined to comment further, simply saying, “It’s a privacy issue, and I’m not going to comment on it.”

Lions cornerback Eric Wright expressed his concern after Thursday’s practice.

“It’s unfortunate,” he told the Detroit Free Press. “Just pray for him and hope for the best. I know everything is going to turn out well for him. That’s all we can do.”

Harrison joined Detroit after the lockout following one season as a backup in Philly. He was drafted by Cleveland in the fifth-round of the 2006 draft. Harrison had his best season in 2009 with the Cleveland Browns when he rushed for 862 yards and five touchdowns in 14 games.

With Lions starter Jahvid Best out with his second concussion of the young season, Harrison was expected to see more action in the run game. This season he has just 41 yards on 14 carries.