The player taken from the practice field in Berea, Ohio on Saturday was Browns offensive lineman Ryan Miller.
According to Mary Kay Cabot of the Cleveland Plain Dealer, Miller was awake, alert, and had movement in his extremities.
Acquired in the 2011 draft with the sixth-round pick that came to Cleveland with running back Peyton Hillis for quarterback Brady Quinn, Miller played in eight games last season.
He was taken to the Cleveland Clinic main campus for further evaluation.
UPDATE 8:01 p.m. ET: The Browns have announced that Miller has a concussion, and that he likely will be released from the hospital tonight.