The Chile international was heavily linked with a transfer away from The Emirates in the summer transfer window but a move for the 28-year-old failed to materialise.
Sanchez has less than 12 months left on his current contract with the Gunners and Arsenal are now facing the possibility of the attacker leaving the north London side on a free transfer next summer.
Arsenal were linked with a late bid to try and bring Thomas Lemar to The Emirates from Monaco as the transfer deadline approached, but the move did not go through.
Now, Wenger has appeared to suggest that Arsenal will have to spend at least £60m on finding a replacement for Sanchez if he does leave the club next summer.
Wenger told beIN Sports: “You take Sanchez into the final year of his contract, you sacrifice £60-70m income.
“At the end of the season you will have to buy somebody for that amount of money. He has a huge price, so at some stage you have to make a decision.”
Arsenal are currently preparing for their Premier League clash against Bournemouth at The Emirates on Saturday.
Sanchez could be in line to make his second appearance of the season after the Gunners lost 4-0 to Liverpool before the international break.
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