Running back Jerome Harrison underwent surgery Friday to remove a brain tumor that was discovered during a physical after he was traded from the Detroit Lions to the Philadelphia Eagles last week.

The surgery went well and doctors believe they removed all of the tumor, ESPN’s Chris Mortensen reported. It is believed that an arteriovenous malformation, an abnormal connection between veins and arteries, may have contributed to the growth of the tumor.

Lions cornerback Chris Houston confirmed that Harrison had had surgery after the Lions’ loss Sunday night. “Guys want to rally behind [him],” linebacker DeAndre 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.”

The trade, which would have sent running back Ronnie Brown to Detroit, was voided; Harrison was placed on the reserve/non-football illness list and is no doubt counting his lucky stars that he was traded.

Harrison complained of headaches during his physical and Eagles team physician Gary Dorshimer ordered an MRI, which revealed the tumor.