Are you surprised by the news that Manchester United have accepted an £80 million bid for Ronaldo from Real Madrid?

David Gill, the United chief executive, spoke to BBC's Sportsweek recently and gave no indication that Ronaldo wanted to leave United. However, the suspicion has been that this attitude has changed because United have been quiet on the topic over the past three weeks.

Remember that in December Sir Alex Ferguson said that "he wouldn't sell a virus to that mob", but United's denials have been less vehement since then.

Was there an agreement in place that United would sell Ronaldo if Real met a certain fee for the player?

80m reasons why Ronaldo sale made sense

Sir Alex Ferguson and David Gill both knew that when Real came in with £80m bid it was simply an offer they could not refuse

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This will become clearer over the next 24 hours. Could there have been a deal struck between Ramon Calderon, Florentino Perez's predecessor as Real president, and Ronaldo's people or an agreement with United as well? United have always denied that such a deal exsisted.

Was £80 million too good to refuse for United?

It wouldn't have been too good to refuse last summer, but another year into a contract that ends in 2012 means that Ronaldo's value will have fallen. The perception is that even such a great player will not be able to repeat his performances between 2006 and 2008 and he was not quite as effective last season.

Ronaldo has also indicated that he has wanted to join Real in three of the past four seasons. Also, if his heart is really set on leaving then is it really worth United keeping an unhappy player? In explaining their decision to sell, United will probably portray him as wanting to leave the club rather than that they wanted to sell him.

Will United reinvest the money in their squad?

The club's annual net transfer spend is £25 million so in theory this will be boosted to £105 million. However, it is not that simple. We don't know if the fee will have certain conditions attached. It could be that United have to spread the money over four or five years.

United's problem is that they will have to replace Ronaldo with not one but two new players: a brilliant winger and a prolific goalscorer.

Franck Ribery is an obvious candidate to fill one of these roles. Real were interested in him and you have to wonder whether an agreement has been struck whereby Real ended their pursuit of the Frenchman to allow United the chance to try and sign him. However, Bayern are reluctant to sell the winger. Other players United might consider are Valencia's David Villa and Karim Benzema, the Lyons striker.

It is unlikely that Ronaldo's move would mean that United will sign Carlos Tevez permanently as the club and the player's advisors are too far apart in their valuation of the striker and his wage demands.