The Gunners duo have little over six months remaining on their current deals to prompt relentless speculation surrounding the duo.
Arsenal could lose Ozil and Sanchez for nothing next summer unless the FA Cup holders decide to cash in on the pair in the summer.
Ozil has scored four goals and has made five assists in his last 10 appearances to prompt talk of a move to Manchester United.
Manchester City attempted to sign Sanchez in a £60m deal in the summer but Arsenal refused to sell the Chile international.
However, former Spurs boss Sherwood believes Arsenal will have to spend £80m on a ready-made replacement for Ozil or Sanchez.
“Arsenal are going to lose two world class players. How much is it going to cot to replace them?” Sherwood told The Debate on Sky Sports.
“You can go with a cheap option but it takes longer. The kid could be developing and he could be worth £50m or £100m in time.
“To get someone who will guarantee that he will do a job is probably going to cost £70m or £80m right away.”
Arsenal finished in fifth place in the Premier League last term to miss out on a Champions League spot last term.
The Gunners won their third FA Cup crown in four seasons following Arsenal’s 2-1 win against defending champions Chelsea at Wembley.
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