As in 4-6 weeks -- that's how long Irish nosetackle Ian Williams, arguably the team's best defensive player this season, will be out after suffering a sprained knee ligament (MCL) against Navy on Saturday.
''It's an injury that some come back quicker than others,'' coach Brian Kelly said. ''We'll be able to get a better feel for it probably next week after we get it to calm down and go from there.''
Kelly said Williams was not a victim of Navy's borderline legal blocking schemes -- cut blocking and high-low chop blocking.
''Ian was double-teamed virtually every play so he was in there battling on every play,'' Kelly said. ''It's hard to really look at any particular block and say, 'That was high low.' I didn't feel that way. Our coaches didn't feel that way.''
Elsewhere on the injury front, Kelly said wide receiver Theo Riddick will be out at least three more weeks with a sprained ankle. Michael Floyd, who also did not play against Navy, ''is feeling better'' but his status for Saturday's game against Tulsa at Notre Dame Stadium will be determined later in the week at the earliest.
Linebacker Carlo Calabrese suffered a pulled hamstring against Navy and ''we are hopeful he'll be able to [play] on Saturday,'' Kelly said. Sophomore Dan Fox had seven tackles in place of Calabrese against Navy.
Safety Jamoris Slaughter, who missed the Navy game with a stubborn ankle injury, also is feeling better but his status for Saturday also is unknown. Sophomore Zeke Motta had five tackles in place of Slaughter against Navy.