The 19-year-old was an ever-present feature for Ajax last term, in addition to being a Bafana regular and captaining the national team to COSAFA Cup honours in June.
Coetzee is also expected to be part of the South Africa U-23 team that will travel to the Rio Olympics next month.
"He (Coetzee) is one player that we have to manage very carefully because he is still relatively young and has played a lot of football," said Urban Warriors assistant coach Mich d’Avray said.
"I know it's part and parcel, he has been chosen for the national team, U-23 team and is now going to the Olympics. So when he gets back we will have to manage that boy carefully because I would hate it if he had to break down during the season because of the number of games and the lack of rest that he may not have."