ABC News' John Muller and Miseon Lee report:

This morning U.S. Naval Academy football player Will McKamey is in critical condition in a Baltimore hospital after he was knocked unconscious during practice this weekend.

McKamey, 19, is now in a medically induced coma after he underwent emergency surgery to relieve pressure on his brain.

McKamey, who is from Knoxville, Tenn., signed as a slot back with the Naval Academy last year. His father tweeted overnight, "Please pray to the father in his son's name that Will turns a corner."

The red-shirt freshman also suffered a serious head injury in 2012 while playing for his high school, but was back on the field a week later.

"I was in the hospital, actually that was one of the scariest things, so just to be blessed with the ability to come back and play and just recover so quickly is great," McKamey said at the time.

The two-time all-state selection went on to be named "Mr. Football" for the state of Tennessee and signed with the Naval Academy after graduation.

Now, his family, desperate for another miracle recovery, said in a statement, "We wish to thank everyone for their prayers and support during this difficult time. We are a strong Christian family and our faith is sustaining us. Will demonstrates his faith every day as a wonderful young Christian man of whom we are so proud. We ask for your continued prayers and to please respect our privacy. Thank you."

In a statement the U.S. Naval Academy said, "Navy freshman slot back Will McKamey (Knoxville, Tenn.) collapsed Saturday morning at a Navy spring football practice. McKamey was flown via Medevac to the University of Maryland Shock Trauma Unit in Baltimore where he is currently undergoing medical care. McKamey, who is a member of the Third Company at the Naval Academy, is a 2013 graduate of Grace Christian Academy in Knoxville. The entire Naval Academy family is shaken by this turn of events and we are providing all the support we can to Will and his family. More information will be provided as it is made available."