"Ben's not had any luck," Sir Alex said at his Friday press conference. "He was coming on fantastically, he's been training really well. I made him substitute on Wednesday, which gives you an indication of his return to fitness.
"He's been blighted by injuries so far in his career. He's a top goalkeeper and I just hope he gets a little break now."
Sir Alex was quick to point out Foster's latest injury is unrelated to the goalkeeper's past troubles.
"This has nothing to do with his previous injury - that was a cruciate knee injury. It was just bad luck."