The veteran centre-back had been tipped to retire by some sections of the British media after reportedly being left out of the club's mid-season training camp in Dubai.
However, manager Moyes dismissed the stories as pure speculation.
"Whatever was written today was a load of rubbish," he fumed. "Complete nonsense."
United visit Arsenal on Wednesday hoping to bounce back from a disappointing 2-2 draw at home to basement club Fulham on Sunday, but Moyes put that result down to persistent bad luck.
"In any other game you would have scored many goals from it," the Scot continued. "We had plenty of chances to win the game.
"We're doing the right things, we need to keep going. Our luck will change.
"Football does that sometimes. We've just got to try to make sure it doesn't happen too often."
Moyes' men picked up a 1-0 victory in the reverse fixture against Arsenal, and the Scot his hopeful his charges can rediscover that form this time around.
"We got a good result against them at Old Trafford and we'll try for the same again," he added. "We're a top side and hopefully we'll show that. We'll do everything to pick up the three points."
Bizarre Jose Mourinho statement aims to pre-empt punishment after Fenerbahce boss clashes with Galatasaray counterpart
'Andy Robertson has a decision to make as a player, where you either roll your sleeves up and give someone great competition or you accept decisions and say that your time is done.' Alan Shearer on the conundrum facing Arne Slot's Liverpool
