Eddie Howe has warned that Newcastle’s hopes of Champions League qualification could well be jeopardised if, as expected, they fail to replace Miguel Almirón.

Howe acknowledges, albeit tacitly, that only a place in Europe’s showpiece competition next season will keep arguably his four most important players, Alexander Isak, Sandro Tonali, Bruno Guimarães and Anthony Gordon, together at St James’ Park.

Related: Jacob Murphy is Newcastle’s unsung hero – just ask Alexander Isak

Yet Newcastle’s manager has also been forced to accept that profitability and sustainability rules dictate that he must work with an “over-stretched” squad. Almirón moved to Atlanta for about £10m this week but Howe said: “As things stand I expect the squad to stay the same after the transfer window closes.”

Almirón’s exit leaves Newcastle with only one specialist right-winger in Jacob Murphy at a time when Isak is the only fit experienced centre-forward and there is a similar lack of left-wing cover for Gordon.

“Miguel’s departure leaves us a little bit short in the position he played, and attacking areas generally,” said Howe before Fulham’s visit on Saturday. “We’re certainly stretched in that area but, as I’ve said many times this month, it was a deal we needed to do. It’s probably not ideal for us in this moment to be light in that [right wing] position but it is what it is. We knew that this window would be a window that we didn’t recruit in. That’s still the case. We’re not actively looking to bring players in.”

Not that Howe is about to throw his toys out of the pram. “I’ve got no problem with dealing with what I know and trying to make the best of the situation,” he said. “So we’ll look at solutions and playing players in different positions if we need to. That’s my job, to try and find solutions.”

Although Murphy has excelled, creating several of Isak’s goals this season, after usurping Almirón in Newcastle’s first XI, Howe is worried about the sudden lack of direct competition for that role. He said: “Two players fighting for the same position is a great thing … Miggy fighting for his place back and training very well kept Murph very much where he needed to be in terms of his performances.”

European qualification could hinge on the solution Howe finds. “The Champions League is definitely where we need and want to be,” said Howe, whose team are fifth in the Premier League, behind fourth-placed Manchester City on goal difference, and hold a 2-0 lead against Arsenal going into Wednesday’s Carabao Cup semi final second leg at St James’ Park. “We’re desperate to get back there … The aim and the ambition is that our top players want to play in the Champions League with us, not elsewhere.”