All three players could miss Milan's round of 16 clash in the Champions League with Tottenham on Feb. 15.
Medical tests Monday revealed that Nesta's rotator cuff wasn't torn, as feared, although the left shoulder injury will likely keep him out three to four weeks.
Gattuso and Seedorf both injured their right legs.
Gattuso should be out at least three weeks, while Seedorf could return in two to three weeks.
Milan holds a four-point lead over Napoli in Serie A.