David Johnson’s injury was termed “severe” by Steelers coach Mike Tomlin, and that doesn’t bode well. Media reports described as a likely a torn ACL in Johnson’s  right knee, which he immediately grabbed after OT Marcus Gilbert rolled on it early in the first quarter. Johnson was carted off the field with a look of disgust across his face and left in a walking cast.

Johnson (two catches, 13 yards) had been playing a position that new offensive coordinator Todd Haley termed “fullback” and even attended running back meetings. Though, on Thursday’s first series of the 24-23 loss at Philadelphia, Johnson played in an offset and almost H-back position.

Johnson was still wearing his regular TE’s No. 85. So, if he indeed will miss the season, do you replace him with a fullback? The only other one on the roster is free agent Will Johnson, who started his West Virginia career as a TE. Or do you replace an absent Johnson with a TE? Rookie David Paulsen and free agent Jamie McCoy would lead the current charge to fill the No. 3 TE role, what with Weslye Saunders scheduled to open the season on a four-game suspension and Heath Miller plus Leonard Pope holding down the first two spots.

As for other injuries from the immediate aftermath of Thursday’s preseason opener:

  • Starting OT Mike Adams, the rookie second-rounder holding the left-tackle spot for Max Starks (ACL) on the Physically Unable to Perform list for awhile longer, injured his right knee on the second series, though it didn’t appear serious. He gave up 2.5 sacks and had trouble on pocket protection battling Eagles DE Phillip Hunt.
  • Backup RB Jonathan Dwyer (two rushes, 40 yards) exited in the first half with a AC sprain in his left shoulder, soon after a 33-yard run that arranged the Steelers’ first TD.
  • DE Cameron Heyward, the ready backup, missed the game due to a back injury. Starting DE Brett Keisel was excused for personal reasons, Tomlin said.

Follow Chuck Finder on Twitter for real-time updates from Steelers training camp @CBSSportsNFLPIT.