Former Manchester City midfielder Dietmar Hamann feels the club needs to be closely monitored by UEFA as deals like the one which has taken Frank Lampard to the Etihad Stadium "could be an issue" in the future.
City were hit with sanctions by UEFA in May for breaching Financial Fair Play (FFP) rules.
This month they recruited Lampard on loan until January from New York City FC - their American sister outfit, who the 36-year-old England international signed for after reaching the end of his contract with Chelsea earlier this summer.
And Arsenal manager Arsene Wenger subsequently questioned the arrangement, saying: ''Is it a way to get around the fair play? I don't know."
Manchester City boss Manuel Pellegrini has responded by insisting "the rules of FFP don't have any relation" to the Lampard situation, which he says has been conducted correctly - and Hamann thinks that deal in itself is not really a problem.
But the 40-year-old German, who played for the Eastlands club between 2006 and 2009, does believe it has set a potentially worrying precedent.
Hamann, speaking in Manchester on Saturday at a McDonald's and Football Association Community Football Day, told Press Association Sport: "I think in the future that sort of thing could be an issue.
"I don't think it is an issue in this case, but in the future, if owners have a player somewhere else and then loan him back, it could be.
"Here it has happened with a player who is 36 and probably way past his best.
"If this was a player who was at his peak, then everyone would say 'hang on a minute - that's not right'.
"We have FFP and you should play by the rules and not try to bend it. This is certainly something that needs to be looked at.
"Everyone should be playing by the same rules - at the end of the day, that is why they brought it (FFP) in in the first place.
"UEFA has to be alert and aware because the clubs always try to get an advantage somewhere.
"I think the first step has been taken with FFP. At least something has been done in the last few years and we are headed in the right direction."
Hamann also believes it is vital work is done at the other end of the football spectrum to ensure the game is healthy at grassroots level.
Speaking about the McDonald's and FA event he attended at Burnage Metro FC, Hamann said: "There are a lot of kids here playing tournaments, and it is just great to see them enjoying playing their football in a competitive fashion.
"It is great that that is being supported, because grassroots football needs that as these are players for the future.
"They will hopefully be the ones playing in the Premier League and for England, and it is always good to promote that because without grassroots football, there won't be any football."