Midfielder Nicholson, who suffered the injury in North End's 2-0 win over Peterborough on Saturday, was set for an operation to insert pins into his leg. However, a revolutionary cast, which allows movement in the ankle and knee joints to assist a quicker rehabilitation, may now mean a pin is no longer necessary.
"One of the things you are not keen to have a cast on for is that while the leg is healing you find that the knee and ankle are totally restricted and most of the rehab work is about freeing them up again," boss Alan Irvine told the club's official site.
"This new cast allows the ankle and knee to move and you can still weight bare. If he's going to get it pinned it will probably be on Thursday.
"Baz is going to be the one that makes the decision, mentally he has got to feel that it is the right decision rather than somebody pushing him down one route or the other.
"The decision will be made and he will be X-rayed in a couple of weeks time and that will give everyone a better idea of how long he will be (out)."