By CHAREAN WILLIAMS IRVING — Nose tackle Jay Ratliff has played like the Pro Bowl player he is. This week, the Dallas Cowboys just hope he plays.Ratliff injured his right knee in practice Thursday, coach Wade Phillips revealed Friday. Ratliff did not practice Friday and is listed as questionable for Sunday’s game against Seattle with a sprain."It’s something we think will get well, but how quickly it will get well we don’t know for sure," Phillips said.Junior Siavii, a fourth-year veteran, would replace Ratliff in the starting lineup.