Nemanja Vidic's successful return from his long lay-off has already provided a major boost.
"Jonny Evans will hopefully be available when we get back," said Phelan. "He's back doing light work on the training ground. We hope he'll be available for the start of the season. He won't have had the games under the belt but, if he's fit and progressing well, we'll push him forward.
"At the moment, Chris Smalling is going to be a bit longer in his recovery. He's had a setback, an injury, and he's progressing slowly."