The midfielder not travelled with the squad to southern Portugal on Monday due to what Forest said was a private matter that was not transfer-related.
Gibbs-White's future remains uncertain, with Forest considering legal action over Tottenham's approach for him and Spurs still hopeful of a deal
Forest, who say they never gave Spurs permission to speak to Gibbs-White, are looking at whether a confidentiality agreement in his £60million release clause has been breached.
He is said to be keen on a move to Spurs but his team-mate Ola Aina has said the 25-year-old has kept professional.
“He's keeping it professional; I don't know the ins and outs of that," Aina told Sky Sports last weekend.
“He was here today, playing, and he's training, keeping fit as normal.“At the end of the day, we're all professionals - we've got a job to do and that's what Morgan is doing right now. He's keeping it professional."