The former Hull City loanee is set for a return to the Premier League after the Dutch club confirmed it has accepted an offer from the Black Cats
The USA international’s personal website stated that a deal had been struck on Friday and he was due for a medical in Wearside on Monday, before the article was later withdrawn.
The Dutch club’s director of football Earnie Stewart confirmed on Friday that AZ had rejected a bid from Sunderland, but the two parties have now reached an agreement, although no transfer fee has been stated.
"I have not had any problems with my teammates and I feel fine here. But when you get the possibility to play somewhere else, you always have to think about it," Altidore told the Sunderland Echo on Thursday.
Altidore netted 51 times in 93 games during his two-year stint in the Netherlands, including the winning goal against PSV in May to help AZ lift the 2013 KNVB Cup.
He has also been in hot form for his national team, breaking a scoring drought with four goals in the month of June. Altidore scored in each of the team's three World Cup qualifiers against Jamaica, Panama and Honduras and also had the opening goal in a friendly win over Germany in May.