Source: Harrison surgery went well

Jerome Harrison's surgery Friday to remove a brain tumor went well and doctors believe they removed all of the tumor, a source told ESPN senior NFL analyst Chris Mortensen.

A condition known as arteriovenous malformation, which is an abnormal connection between veins and arteries that often goes undetected, may have been a contributing factor to the tumor.

Lions cornerback Chris Houston confirmed after Detroit's 23-16 loss to the Atlanta Falcons that Harrison has had surgery for a brain tumor.

Houston says he hopes to visit his teammate once he's able to have more guests, and linebacker DeAndre Levy was hoping to find out more about how Harrison was doing.

"Guys want to rally behind," Levy said. "When you're out on the field, you've got to be able to control your emotions, regardless of what it is, whether it's that or something else."

Harrison was placed on the reserve/non-football illness list after his trade to the Philadelphia Eagles was voided after the tumor was discovered.

Coach Jim Schwartz has remained cautious when talking about Harrison, not saying much about the player's condition.

"I appreciate everybody's concern, but there's only so much we can say," Schwartz said after Sunday's game.

Harrison complained of headaches to Eagles team physician Gary Dorshimer during Wednesday's physical after Philadelphia agreed to trade running back Ronnie Brown to the Lions for Harrison and a draft pick. The doctor ordered an MRI that revealed the tumor.

The test revealed a tumor known as ependymoma in the fourth ventricle of Harrison's brain.

NFL Players Association medical director Dr. Thom Mayer told ESPN that the lesson he wants all players to learn from Harrison's situation is this: Being truthful with team physicians can have a potentially life-saving result.

"I'm just glad that he found out his situation before it could turn into anything a couple of weeks down the road," Brown said Monday. "That's always good that he found that out and got that taken care of. So I'm excited about that."

Chris Mortensen is ESPN's senior NFL analyst. Information from The Associated Press was used in this report.