A report over the weekend claimed that the winger has decided not to train or play for his League One employers in a bid to engineer a switch to the City Ground.
However, Moxey has insisted that the 25-year-old is still committed to the club's cause.
"To suggest he is going on strike is untrue. He has been professional throughout this and as good as gold and we have talked to him and his people every step of the way. Everything has been completely transparent," he told the Express & Star.
"While he is disappointed and we're frustrated, he remains as committed to the cause and we have the utmost respect for him."
Sako missed his side's 3-0 win over Colchester United on Saturday afternoon through illness.