Alexis Sanchez's wages could create dressing-room disharmony at Manchester United, warns Steve McClaren.
Sanchez is expected to complete his move to Old Trafford from Arsenal on Monday, with Henrikh Mkhitaryan moving in the opposite direction.
The 29-year-old Chile forward is set to become United's best-paid player, with some reports putting his salary at between £350,000-£400,000 per week.
"That is the danger in the modern game and the problem I find in clubs," said McClaren, the former England manager and Sir Alex Ferguson's assistant when United won then treble in 1999.
"Wage parity is very important to players. Yes, they find out - at all levels - and if someone is paid a lot higher than others that can cause a problem.
"In the short term I don't see a problem, but in the long term for Manchester United they will have to solve that problem.
"If he (Sanchez) is on the wages that is being bandied about then other players will know that when their contracts come up or they are in demand from other clubs.
"The others will be looking at renegotiation next season or the season after and getting to that (wage) level if they think they are at that level."
But McClaren believes United have struck a major blow by landing Sanchez, who has scored 80 goals in 166 appearances at Arsenal.
"Any manager worth his salt would love to have Sanchez in their team," McClaren told BBC Radio 5 Live's Sportsweek programme.
"Sanchez coming in for the second half of the season at Manchester United is a huge boost to them.
"He has got that experience and toughness, he wins games and he is a leader.
"It will lift the level of the whole club."
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