Liverpool have suffered a major blow in their attempts to strengthen Arne Slot’s midfield after Martín Zubimendi opted to stay at Real Sociedad.

The Spain international was Liverpool’s preferred target for the defensive midfield role their new head coach wants to improve this summer and the Anfield club believed he was keen on a move to Merseyside.

Zubimendi, however, informed Liverpool’s sporting director Richard Hughes on Monday that he has decided to stay at Sociedad. The 25-year-old had previously rejected overtures from Arsenal and Bayern Munich to remain with his boyhood club, who are now expected to offer the midfielder a new long-term contract.

Sociedad had made a concerted effort to keep Zubimendi since Liverpool’s interest emerged last week. The Basque club were reluctant to lose the midfielder after selling the defender Robin Le Normand to Atlético Madrid and with Arsenal targeting Mikel Merino. They had told Zubimendi he would have to force a move to Anfield should he decide to leave by paying his own €60m (£51m) release clause at the La Liga offices in Madrid. Liverpool were prepared to activate that clause only for the Spain international to reject their advances.

Fábio Carvalho has completed his move from Liverpool to Brentford for a fee that could rise to £27.5m.

The attacking midfielder has attracted interest from several Premier League clubs this summer including Southampton and Leicester. Only Brentford met Liverpool’s valuation of the 21-year-old, however, and completed a deal on Monday that is worth an initial £22.5m plus £5m in add-ons. Liverpool will also receive 17.5% of any future sell-on fee. His previous club, Fulham, get 20% of the Brentford fee as part of the terms of Carvalho’s £5m transfer to Liverpool in 2022.

The Portuguese player spent last season on loan at RB Leipzig and Hull having struggled to gain regular playing time under former Liverpool manager Jürgen Klopp. The club’s new manager, Arne Slot, was impressed by Carvalho on the club’s pre-season tour of the US but Brentford’s offer, a significant improvement on the £15m offered by Southampton, was one Liverpool felt could not be turned down.

Brentford’s head coach, Thomas Frank, told the club website: “Fábio is a player with a lot of qualities. He can play in all of the front three or four positions in a 4-3-3 or a 4-2-3-1. His best position is probably as a No 10 or coming in from the left.

“Offensively, he has great abilities on the ball: he can go past players, slide a pass, create chances and get on the end of chances. He’s a type of player that we don’t have many of in the squad so he will add that something extra for us.

“His ability and mentality to work hard in the pressure is also very, very good. That’s along with him ticking all the boxes from a cultural perspective and being the right character. So we’re very pleased to see him come in and push the team forward.”

The Anfield club are also considering an offer of about £10m from Red Bull Salzburg for the 19-year-old midfielder Bobby Clark. Salzburg, now coached by Klopp’s former assistant Pepijn Lijnders, have had two bids rejected so far. Clark, who made 12 appearances for Liverpool last season, also has interest from Premier League clubs.