The Red Devils, who narrowly missed out on retaining their title following a last-gasp effort from Sergio Aguero during Manchester City's victory over Queens Park Rangers on the final day of the season, are due to go up against Everton at Goodison Park on August 20.
"Evans is recovering from an operation," Ferguson told the club's official website. "[Chris] Smalling is out for three months. Jones got a muscle injury in his back and was sent home from Norway.
"So the area we're concerned about is centre-back. Evans won't be ready for the start of the season. He won't be far away but he won't be ready. Smalling is out and I can't give you an update with Jones because we've not fully diagnosed that."
Meanwhile, the Scottish boss has claimed that he is 'hopeful' of securing the signature of Arsenal striker Robin van Persie.