The Manchester United striker has been in superb form during pre-season so far, with McClaren on hand to see two of his best performances, against Inter Milan and then in the Community Shield win over Chelsea on Sunday.
McClaren said: "It is great to see Wayne coming back from his break this summer in top form.
"I spoke to Sir Alex quite early on and he told me how fit Wayne was. He certainly looks very fit from what I have seen.
"It is his first full pre-season for a while as well, so you are bound to benefit from that.
"Speaking to Wayne, I know he is dying to get back into the England squad and he is going to be a big player for us."