Coach Mike Johnston said Friday that Ehrhoff (upper body) won't be able to skate until next week, Jason Mackey of the Pittsburgh Tribune-Review reports. Johnston wouldn't reveal the nature of Ehrhoff's upper-body injury, but there's reason to think he may have suffered a recurrence of a concussion after slamming head-first into the boards in Tuesday's game against the Blues. The Penguins don't appear to have a definitive timetable for Ehrhoff's return, but if he's indeed able to skate next week, the team might shed more light on his condition. Derrick Pouliot is expected to benefit the most from Ehrhoff's absence.