There has been speculation doing the rounds that the Frenchman will be looking for a move next season after struggling in his WSBK title defence on the underpowered Honda Fireblade.
Guintoli is yet to finish on the podium this season as is lying in 6th place in the WSBK standings on 127 points, well behind leader Kawasaki rider Jonathan Rea who sits on 375 points. Van der Mark is in eighth position with 97 points.
Van der Mark told MCN that as far as he was concerned if Guintoli is unhappy then he must go.
"If he's not happy, he has to go. If he finds a better challenge, he has to do it.
"I would do exactly the same. My feeling is that, if Sylvain gets a good chance, he has to do it. That's my feeling," Van der Mark said to MCN.
"I really enjoy having him as a teammate, but at the end of the day we all have to race for ourselves. Sylvain and I have such a different riding style, but we take the best things from each other.
"It is good to have somebody next to you with a different riding style," he added.