The Alkmaar-based side have recorded two wins and two losses in their opening four Eredivisie matches and were 3-1 victors at Dordrecht before the international break.
However, confusion has surrounded the future of head coach Marco van Basten, who replaced Dick Advocaat in the close-season.
Van Basten was not in the dugout for the Dordrecht victory and earlier this month AZ confirmed the Dutch legend was on leave of absence until September 14 amid reports he had suffered heart palpitations following the death of his father in July.
Further speculation on Friday suggested that Van Basten will permanently leave his role with assistant Alex Pastoor ready to step in, although there has been no official word from the club.
AZ face a Heerenveen outfit who have picked up seven points from three games after losing to Dordrecht on the opening week of the season.
Heerenveen also won the corresponding fixture 5-1 last season, although the hosts can take confidence from a 3-1 aggregate victory in the subsequent Eredivisie UEFA Europa League play-off semi-final.
PSV will seek to maintain their outstanding early-season form when they head to PEC Zwolle, who suffered a first defeat of the campaign at NAC Breda last time out.
Phillip Cocu's league leaders have won four out of four thus far, with Netherlands international Memphis Depay responsible for five of their 14 goals.
Defending champions Ajax welcome rock-bottom Heracles, who are without a permanent coach after dismissing Jan de Jonge last month, to the Amsterdam Arena.
Having seen his side lose two games in a row, Ajax coach Frank de Boer - who could hand a debut to midfielder Niki Zimling - insists another defeat will not be accepted.
"In the coming period the team must guard against naivety. There will be a busy period with duels in the league, cup and Champions League," De Boer told the club's official website.
"Hopefully we put a few good results together and get into a flow. To lose three times in a row is not an option."
Ryo Miyaichi could make his bow for winless Twente against Go Ahead Eagles on Saturday, while Feyenoord host Willem II.
Groningen have started the season strongly and Erwin van de Looi's men - who sit second - travel to Cambuur on Sunday buoyed by a 2-0 triumph over Ajax in their last league match.
Elsewhere on Sunday, second-bottom Vitesse will look to kick-start their campaign at home to Excelsior, Utrecht face off with ADO Den Haag and NAC visit Dordrecht.
