Gayle has been given a period of complete rest as Newcastle boss Steve Bruae struggles to get to the bottom of the striker's calf troubles.
"We're doing everything we can. We've had scan after scan and specialist after specialist. We just can't seem to get to the bottom of it so it's now complete rest," Bruce told the Evening Chronicle.
"We've just come off it totally and hopefully that will maybe do it the world of good. As I said, he trained the day before we left China so I thought, 'He looks as if he's going to be OK. He's training well.' It's a problem. It's a problem because we can't get to the bottom of it."