Best picked up the injury during last weekend's Magic Round loss to the Wests Tigers in Brisbane. He finished the game but complained of hamstring tightness after cooling down.

It hasn't improved enough since then with coach Adam O'Brien not prepared to take the risk of playing him against the Cowboys despite the importance of the game.

The loss of Best means the Knights will go into the match without five of their regular starting backline, with halfback Mitchell Pearce, fullback Kalyn Ponga and wingers Edrick Lee and Hymel Hunt all on the injured list as well.

Ponga, who is recovering from a slight groin tear that also kept him out of the Tigers game, will be strongly in the mix to return against Manly on Sunday week along with Best, whose injury is not considered serious.

There is little doubt the Knights' task of bouncing back and beating the Cowboys following their abysmal performance against the Tigers has been made that much more difficult with Best's withdrawal.

With Pearce, Ponga and now the powerhouse teenage centre all sidelined, it is difficult to see where the Knights' points will come from to pressure a Cowboys side showing signs of emerging from their own early season battle for form.

O'Brien has been given some injury relief with veteran playmaker Blake Green returning from a cracked rib and named in the halves alongside Phoenix Crossland. Regular five-eighth Kurt Mann has been moved to accommodate him.

IN NEWS TODAY:

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to support us: