"Kevin has a big year ahead of him next season. He is coming into the last year of his contract," Keegan told the Evening News.
"We will have a look at him up until Christmas and then decide, but so far we are pleased with what he has done.
"He has come on and developed for having the games in the senior side. His inexperience was why I brought Arni in."
Arason, who turns 29 tomorrow, is likely to play for Iceland in the triangular tournament at COMS. However, they could be his only appearances there, should Keegan opt for Ellegaard ahead of Arason as James' long-term deputy.