Philadelphia Eagles defensive tackle Mike Patterson has a rare brain condition that most likely caused his seizure this week at training camp, the National Football League (NFL) team said on Thursday.

The Eagles' first-round pick in the 2005 NFL Draft was hospitalized after suffering a seizure on Wednesday for about four minutes and losing consciousness at the team's training camp in Bethlehem, Pennsylvania.

He has been diagnosed with brain arteriovenous malformation (AVN), which means there is a tangle of blood vessels in his skull outside his brain, said Eagles trainer Rick Burkholder.

Burkholder would not speculate as to what type of treatment Patterson, who was expected to leave the hospital on Thursday, would need.

The trainer also would not say when or whether Patterson could play football again.