According to John Carroll, head coach at Northfield Mount Hermon (Ma.), Aaron Cosby will be out for 4-6 weeks due to a sprained posterior cruciate ligament (PCL) that he sustained in practice. In a somewhat conflicting report that looks to be from the coaching staff, it appears that Cosby may be back towards the front end of that time table. Based on these two reports, I would venture a guess that Cosby has a Grade 1 sprain that doesn't require surgery. While he may be back in action within a few weeks depending on his recovery, expect a knee brace and a player who doesn't have their full mobility -- PCL injuries take several weeks to fully heal.
Matching Cosby's time table with Seton Hall's schedule, it looks like he will return sometime in late November. While this is a lot more favorable than a season ending ACL injury, it looks like Aaron will be absent for some of the more challenging non-conference match-ups, most notably Washington, Ohio State/Rhode Island and LSU (away). Seton Hall should be able to handle their other less talented non-conference opponents without Aaron, who may have been Seton Hall's starting point guard against UMKC on opening night. Cosby's natural position, shooting guard, looks to be filled by the dangerous duo of Brian Oliver and Haralds Karlis while Tom Maayan and Freddie Wilson take over the reigns at point guard.