Danny Welbeck has expressed his frustrations about the frequency with which he has been played out of position at Manchester United, rejecting the chance to say he wanted to be part of the Louis van Gaal era and making it clear that he is still contemplating leaving the club despite the arrival of the new manager.

Welbeck, speaking for the first time about the uncertainty surrounding his future, said he had started to feel disaffected because of his “frustrating” inability to establish himself in the central role he craves. It had been his “unhappiest season, without a doubt” and the player is concerned it will continue that way when Van Gaal takes charge after the World Cup. “I’d like to play centrally,” he said. “I’ve been playing on the left for a while and it’s got to the time when I want to stake a place up front.”

Those chances appear slim, as Welbeck is aware, when the competition is provided by Robin van Persie and Wayne Rooney and especially when United’s exploratory talks about Edinson Cavani’s potential availability from Paris St-Germain demonstrate they are open to the idea of bringing in another attacker. Welbeck’s advisers have already let United know he is willing to sever his ties with the club, albeit reluctantly, and Tottenham Hotspur are among his admirers. Asked directly whether he could clarify that he still wanted to leave, he replied: “I’d rather not answer that question.”

Welbeck was subsequently asked whether it had reached this point because of his desire to play as a centre-forward. “Yes,” he said, “it does get frustrating. You want to play in a certain position and you’re not getting the opportunity to do that. It’s the same for everyone else when they are being played out of position and they don’t really like it.”

The 23-year-old is often criticised for his goal output but made the point that, as a wide player, it was regarded as “a bonus” to score. His issue is particularly when United operate with a 4-4-2 system. “It depends what formation we are playing. On the left of a four-man midfield there are a lot more defensive duties so you can’t find the time to keep attacking. But if you’re on the left of a 4-3-3, I find that position really good. I can play in any formation but, if I play on the left, I’d rather play there if there are three in midfield.”

Ideally, though, he wants the chance to show he can score regularly as an orthodox striker. “I played there for United over the Christmas period and scored a few then. I just want opportunities.”

Welbeck said he had become particularly unhappy over the last season – “I’d rather not think about it,” he replied, when asked to elaborate – and is known to be one of the players who found it difficult accepting David Moyes’ style of management. At one point Moyes publicly stated that Welbeck should put in extra work on the training ground, a statement that went down badly with the player. “I was pretty surprised, to be honest. I’ve grown up at Manchester United and been professional all through my career and I always do extra work. It’s born and bred in me to do extra work after training. He came out with that statement but, before then, I had been doing extra training. Maybe he just didn’t see it.”

To illustrate the point Welbeck took a personal fitness trainer with him to Dubai when the members of Roy Hodgson’s World Cup squad had a week off before joining England’s training camp in Portugal.

“I wouldn’t say I play better for England but my goals-per-game ratio is definitely better,” he continued. “Formation-wise, I’m much freer up front because, when I play on the left for England, with three in midfield and three up front, there is more defensive cover rather than me being that defensive cover. For United I’m more likely to be left-wing in a four-man midfield, with only two central midfielders, so it’s a bit more difficult for me to make runs and score goals when I’ve got to think about my defensive duties. Maybe I’m let off the leash a bit more for England than United.”