He told the Shields Gazette: "It's disappointing, because the reality is that Newcastle United are delighted that England regard Michael so highly.
"It's quite right that they should, because he is clearly a tremendous striker for his country, as well as for Newcastle United.
"I appreciate that the pinnacle of every great player's career is not just representing their club in every way they can, but also representing their country.
"And I wouldn't want to hold any player back in their desires to play for their country.
"Michael is a prized asset to this club and we want to look after him, but we appreciate that he wants to represent his country as well."