The ex-England C international, who has played for Aldershot and Grays, joined Posh from Athletic in 2007 for £150,000 after a three-month loan spell.
Mclean has scored 82 goals for the club, helping them to successive promotions in 2007/08 and 2008/09.
Peterborough owner Darragh MacAnthony revealed earlier this week that he would consider selling his star names if they are unhappy at London Road.
Mclean has been on the transfer list since November 2009, but has started every league match for the Posh this season
Source: BBC Sport
Source: BBC Sport