Reports have emerged that McClaren, who was appointed just 11 weeks ago, has retreated to his north-east base to think about his position after becoming increasingly frustrated at a lack of investment in his team.
But the npower Championship club were unavailable for comment on Friday morning while McClaren's agent Colin Gordon declined to comment when contacted by Press Association Sport.
The former England manager saw nine players leave Forest over the summer, but brought in just four replacements, spending £2million pounds as Ishmael Miller, Jonathan Greening, George Boateng and Andy Reid came to the club.
McClaren was reported to be denied several moves in the transfer market on deadline day and to make matters worse, he has seen promotion rivals Leicester and West Ham spend big over the summer in their attempts to earn promotion to the Barclays Premier League.
The 50-year-old, who returned to English football after spells in Holland and Germany, is thought to be irked by the fact he was told funds would be available for transfers.
At the time of his appointment in June, Forest chief executive Mark Arthur said: "Money has been available in the past. (Chairman) Nigel Doughty has put £25million into the club in the last two seasons.
"Steve will have similar funds available to him if he can identify a player of the quality who will enhance the quality of the current squad."
The manager complaining about lack of transfer activity is nothing new for Forest fans to endure as former boss Billy Davies, whom McClaren replaced, regularly spoke in public about his frustration.
Forest's start to the season will have done nothing to boost McClaren's mood, as they currently sit 18th in the Championship with just five points from their opening five games.
Source: PA
Source: PA