No, I do not think that Seton Hall will be able to replace Isaiah Whitehead next year because Whitehead is considered one of the top guards in the country and is definitely going to get picked in the first round of the NBA draft. I believe that it will be very tough for Seton Hall to find a replacement to Whitehead.
While Isaiah Whitehead has certainly been leading the Seton Hall Pirates to victory all season, it is important to remember that basketball is a team sport that requires the efforts of all players on the court. If anything, I think that his efforts this year and the success that the team as had will just be extra motivation to succeed in seasons to come.
Seton Hall will be able to replace Isaiah Whitehead next season because it is an elite basketball institution that is capable of recruiting elite players from across the country. It essentially gets to pick the best athletes from the litter. Colleges like Seton Hall have little trouble finding excellent players to replace anyone who leaves the team.
Seton hall will lose Isaiah Whitehead but does have a strong recruiting class coming in next season. After the dismantle of the Big East conference in 2012, the Pirates have had a few rough seasons. They were able to get back on track this year and made a run in the NCAA tournament. They will build on this next season and use this experience to guide them.