Sepulveda tore the ligament on the first day of practice Monday. The Steelers used undrafted rookie kicker Julian Rauch of Appalachian State as their practice punter Tuesday, but claimed former Broncos punter Paul Ernster on waivers from Detroit.
The Steelers traded a sixth-round draft pick last year to move up in the fourth round and draft Sepulveda, a former Baylor star who is the only two-time winner of the Ray Guy award as the nation's top college punter. The Steelers had drafted only one other punter in their history.
Sepulveda averaged 42.4 yards and placed 28 of 68 punts inside the 20 as a rookie last season, so the Steelers didn't bother bringing a second punter to camp.
The 6-foot-3, 230-pound Sepulveda is expected to have surgery in the next few days. He first tore the ligament while playing pickup basketball at Baylor in April 2006, but returned -- too early as far as his doctors were concerned -- to punt in the school's season opener that September.