Polter has been one of QPR’s best performers under the Dutch boss so far, and he seems to have become the side’s main attacker.
However, Hasselbaink says that the powerful forward needs to start doing more if he is to nail down his position in the starting line-up.
“We know what he has got,” Hasselbaink said. “We know his work ethic. But I think he needs to do more. He can even bring more.”
Polter came on as a substitute for QPR in their match against Leeds United, and he helped the London side pick up a point.
The former Mainz man won a late penalty, which Tjaronn Chery converted to ensure that Rangers did not leave empty handed.
Polter’s main competition for a striking place at QPR is Conor Washington, but the January signing struggled again at Elland Road yesterday.
Washington has not scored in his first nine appearances for QPR since signing from Peterborough United, and it seems likely that Polter will come back into Hasselbaink’s starting line-up in the coming weeks.
QPR’s next match comes against Charlton Athletic at Loftus Road on Saturday.