Arsène Wenger has suggested the expected loss of Alexis Sánchez as a Bosman free agent at the end of the season will cost Arsenal up to £140m. The club received an offer of £60m for the forward from Manchester City before the closure of the summer transfer window and they were inclined to accept it, even though they wanted nearer to £70m.

Sánchez, who had told Arsenal he desired the move and has made it plain he will not renew his contract, ended up staying put after the club failed to complete a deal for Monaco’s Thomas Lemar, whom they had identified as the attacking player to place him.

Wenger has always said he would rather keep Sánchez for the final year on his contract – such is his importance to the team – and he believes the player will remain motivated as it is in his interests to play well and impress other clubs.

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Wenger totted up the financial hit Arsenal are likely to take by adding together the lost transfer fee on Sánchez and the cost of replacing him. He put the later figure at between £60m-£70m, although he had gone as high as €100m (£92m) with his deadline-day offer to Monaco for Lemar. Wenger has said he will try again for the France winger.

“You take a Sánchez into the final year of his contract, you sacrifice £60-70m income and at the end of the season you will have to buy somebody for that amount of money,” Wenger told beIN Sports. “It has a huge price so, at some stage, you have to make a decision; you have to sacrifice one or two.”

Sánchez has endured a nightmarish week or so. First, his move to City collapsed on deadline day last Thursday and then he suffered World Cup qualifying losses with Chile to Paraguay and Bolivia. Chile sit sixth in the South American standings, with two games to play. Only the top four countries qualify automatically for the finals, with the fifth-placed team entering a play-off.

Sánchez poured out his heart on Instagram after Tuesday’s Bolivia defeat, saying he was “tired of being criticised” and referencing the “huge responsibility” he felt on his shoulders.

Wenger will have to lift him before Saturday’s home fixture with Bournemouth in the Premier League but he warmed to a recent theme of his when he highlighted the rising number of players to have entered the final year on their deals.

“We have today 107 players in England who go into the final year of their contract,” Wenger said. “It’s a complete rotation and change in the way people see their careers. All the players expect higher wages because they anticipate inflation and, because the transfer market has gone up so much, the clubs do not want to pay such high prices for players who are good but will not change their lives.”

To Wenger, the very top end of the market has been distorted. “The amount of money is completely disconnected to reality and the truth,” he said. “Ousmane Dembélé last year was €15m; this year, he is €150m. No matter how well you work as a coach, you cannot make a player go from €15m to €150m. The calculation between investment and what you can get back has gone. It’s just: ‘Can you afford to buy or not?’”