The Uruguayan forward has been linked with a move away from the La Liga side throughout the summer after the upcoming boss reportedly told him he was no longer in his plans.
However, the Barca coach revealed that Suarez could still have a part to play should he not leave the Nou Camp.
Speaking after his team's friendly win over Girona, Koeman said: "Suarez will be one more [member of the squad] if he stays.
"I was talking to Luis this morning. We will wait to see if there is a way out or not. We respect contracts and, from day one, we have said that if he stays on the squad, it will be one more."
The Dutchman also praised Phillippe Coutinho, who spent last season on loan at Bayern Munich and urged fans to get behind the star.
Coutinho scored in the victory and look set to remain at Barcelona for this season, despite having a difficult spell at the Catalan club so far.
Koeman told TV3: "He is in high spirits at the moment, training and playing well.
"He has great quality. We must bear in mind that he needs the support of the coach and the fans."