On Tuesday morning it was reported that Wilson was refusing to take any further part in the club's pre-season games because Forest would not allow him to speak to the Scottish Premier League giants.
Neil Lennon's side were thought to have had an offer in the region of £1million turned down by the midlands outfit.
However, a club spokesperson told Press Association Sport that the reason for the centre-back's current absence is a shin injury.
"We can confirm that Kelvin has an injury," said the spokesperson.
"He took part during the pre-season trip to Portugal but since he returned he has picked up a shin injury and that is the reason he has not played."
The spokesperson refused to comment on whether Celtic had made a formal offer for Wilson, but added: "We have no idea where these stories about going on strike have come from."
Source: PA
Source: PA