Ellington is training with the Railwaymen following his release by Ipswich on transfer deadline day.
"At the moment we've made no decision," said Davis. "He needs to keep getting fit and showing us that little bit more.
"It's not really a trial period. He asked us if he could come and train and use the facilities.
"We've allowed him to do that and that's given us a chance to have a look at him.
"He's not on a trial, as such, but we've said we'll have a look at him while he's here."