The Penguins have the best collection of centers in the NHL and one of the league's deepest defense corps. On paper, anyway. That has not, however, been the case for games very often over the past year or so. And they got more bad medical news, when it was determined that center Jordan Staal would have to miss their game Saturday night against the New York Islanders at Nassau Coliseum because of an unspecified injury he apparently sustained in the 3-2 loss against Philadelphia two nights earlier. Staal sat out the Penguins practice Friday, but participated in the first 10 minutes or so of their game-day skate Saturday before adjourning to the locker room and not returning. Coach Dan Bylsma described him as "day to day at this point in time."