Racing community tweets concern for Wilson

Justin Wilson was airlifted to Lehigh Valley Hospital-Cedar Crest in Allentown, Pennsylvania, Sunday evening with a head injury after it appeared he was struck on the helmet by debris from Sage Karam's one-car crash in front of Wilson on the track.

Wilson is in a coma in critical condition while undergoing further evaluation, according to a statement released by INDYCAR.

The racing community, including Wilson's brother Stefan Wilson, shared their hopes, prayers and concern on Twitter.