Hernandez appeared to endorse comments on Twitter made by his Mexico striker partner Carlos Vela, who suggested he should quit United for more regular first-team football.
The former Guadalajara forward has made only one Premier League start this term and despite scoring three times in the two games prior to Saturday's top-flight win at Fulham, he was an unused substitute for the clash at Craven Cottage.
Wayne Rooney and Robin van Persie are on a hot run of form in the United attack but Moyes, speaking ahead of United's Champions League clash with Vela's Real Sociedad, shrugged off suggestions Hernandez might be moved on.
"We need Javier Hernandez; he's very good for us," Moyes said.
"He's scored a lot of goals over the last few years and continues to do so, so we'll continue to use him."
Vela had been quoted as saying over the weekend that his fellow Mexican may have to consider moving on, insisting there would be a host of clubs interested.
"He is one of the best finishers in England and deserves chances under the new coach.
"If he plays regularly he will score, so I don't totally understand why a player of his quality has not played more games.
"If he doesn't play regularly he will need to think about leaving.
"You always want to succeed at the biggest clubs - but if he is not given the chance there will be big teams in England and Europe wanting him."
Moyes and keeper David de Gea are in total agreement that United cannot afford to take Sociedad lightly.
United go into the match with seven points from their three Group A outings, and requiring just one more win to reach the 10 Sir Alex Ferguson always felt was enough to secure a knockout berth.
Given their opponents have yet to muster so much as a draw on their return to the elite competition after a 10-year absence, the task appears straightforward.
Moyes and De Gea are united in their belief looks can be deceptive.
"I certainly won't take anything for granted," said Moyes.
"I have a lot of respect for Sociedad, and we will have to play well on Tuesday if we are going to get those 10 points which will get us over the line."
De Gea added: "It's very difficult to play at the level Real Madrid and Barcelona are at.
"They might not be at the top level yet but it's obvious Real Sociedad have been playing great football over the years."