Reid wrote in the Daily Star Sunday: "Both City and United are in the race to sign Robin van Persie from Arsenal but there is no guarantee that signing him would make the difference in terms of winning the title.
"He is a top-class finisher but I wouldn't pay £30million for him.
"That would be a gamble in my opinion, because he is 29 on August 6 and has had a lot of injuries.
"As he has only a year left on his contract, a more realistic fee would be £10-£15m.
"Arsenal don't want to lose him but why weren't they trying to tie him up with a new contract a year ago?
"Maybe it could be because of all his previous injury problems."