Queens Park Rangers have failed to win any of their last three matches.
Hasselbaink has made alterations to his starting line-up at QPR in recent times, with a range of players being handed rare first-team chances.
The Dutch boss started with both Cole Kpekawa and Ben Gladwin during QPR’s match against Reading yesterday.
And he said: "With two more games this season, if you’re not already starting to plan for next year then you will have a big problem. You need to plan in advance.”
Hasselbaink has already had one transfer window at Loftus Road, and his strategy was clear from the type of players he brought in.
QPR signed Conor Washington, Nasser El Khayati and Matt Ingram from lower levels in January and it seems that more players from similar backgrounds could arrive in the summer.
“It is clear the direction we need. We have to have younger players – more assets in the club,” Hasselbaink said.
“We have to look at more players who are 23, 24 or 25. I’m not saying we shouldn’t sign a 30-year-old, but in the past few years too many players have come here to retire.”
QPR have shown signs of progressing under Hasselbaink, but their current run of form is poor.
Rangers have failed to win any of their last three matches, and they have slipped down to 13th in the Championship table, as a result.
QPR are next in action against Burnley in two Mondays’ time.