According to ESPN, although Celtic are likely to reject the offer because of the player’s importance to them - he scored in the home Champions League win over Barcelona - it would send a statement of United’s intent to move to the front of the pack chasing his signature.
The Kenyan’s performances have attracted interest from a number of clubs in the last few months and, with several preparing to open talks with the Scottish Premier League champions and the player, it is believed United feel they must act now.
Sir Alex Ferguson took a look at Wanyama during Celtic's 4-0 win at home to Dundee United last week. Nevertheless, it appears the player may only be a fall-back midfield option for United in the event that they fail to land their main target, PSV Eindhoven's Kevin Strootman.
The move for the highly-rated Dutch player is understood to be threatened, however, by United's unhappiness with his agent - and that could mean they are prepared to look elsewhere.