David Moyes will be backed by the Glazer family in the January transfer window should he wish to spend heavily, with the Manchester United manager considering a potential £50m move for Everton's Leighton Baines and Athletic Bilbao's Ander Herrera.

However, the Scot will sanction bids in the market only if he feels there is requisite value, to keep in line with club policy regarding transfers.

Given Everton rejected a £15m bid for Baines in the summer, United are conscious it may take an offer of £20m-plus to sign the left-back, as this would be the level of fee that Bill Kenwright, the chairman, may find impossible to refuse.

Any move for Herrera could require United coming close to or breaking their club record £30.75m fee to activate the midfielder's €36m release clause after Athletic refused a £25.6m bid in the summer – wanting to hold out for the full price.

There is also a recognition at United that while there was no panic during the summer window there are lessons to be learned, with one consideration being that Moyes's contract at Everton might have been bought out early so that he could start work instantly on targets, rather than wait until 1 July when the 50-year-old officially signed on.

In the event, the window ended in a final-day scramble to sign Marouane Fellaini from Everton while the proposed deals for Baines, Herrera and Real Madrid's Fábio Coentrão collapsed, as had the earlier move to buy Barcelona's Cesc Fábregas.

The Glazers' willingness to back the Scot in January reflects an understanding that the first transfer window for Moyes and Ed Woodward, the new executive vice-chairman, was always going to be difficult. Beyond this, the owners recognise that the Premier League has become far more competitive this season following the managerial changes not just at their club but also at Manchester City and Chelsea, plus the renewed investment in those squads challenging for a Champions League berth.

Tottenham Hotspur, having sold Gareth Bale for a world record £85.3m, have strengthened their squad considerably as have Arsenal, who spent £42.5m on Real's Mesut Özil.

Arsène Wenger's side head the Premier League but Tottenham are only two points behind in third place, with Liverpool, who have also made a strong start to the season, in second position.

Although Moyes and the executive vice-chairman understand that January can be a difficult market to operate in, the manager's start to the title defence – only seven points from six games, with three defeats – has confirmed the need to invest in a squad in which many of the players are ageing.

Moyes's comments about the strength of the squad and his assertion at the weekend that there are no guarantees United will qualify for the knockout phase of the Champions League will have been little surprise to the hierarchy. United fly out to Ukraine before their second group game against Shakhtar Donetsk at the Donbass Arena with Moyes looking for a return to the winner's circle in readiness for Saturday's trip to Sunderland.

Alexander Buttner, who played in Saturday's 2-1 home defeat by West Bromwich Albion, claimed that despite the club's start being the worst since 1989, there is no crisis. "We have lost three games but we have to focus in every game and we have to fight in every game to win," said the Dutchman.

"We are not in crisis. Of course the crowd wants to see Manchester United winning – and the players as well. If we lose we aren't happy, we want to win as well and we have to fight in every game to win. This season starts now and we can win many games. You have to trust the players and everyone. I think we can do this as a team and we're going to win games, I'm sure."

The left-back views the game with Shakhtar as a quick chance for the club to move on.

"We have to focus on Wednesday's game. Of course it's very disappointing to lose the game [against West Brom] because we played a good game and won against Liverpool [in the Capital One Cup] Now we lose at home against West Brom, so it's very disappointing for everyone."