Liam Martin is set to return back to the sidelines after the back-rower aggravated his hamstring against the Knight on Saturday.

In what was Martin's return match from injury, he was only able to last a total of 34 minutes on the field. Having not played Round 3, he was hoping for a successful return to the field.

Confirmed by coach Ivan Cleary post-match, he has re-aggravated the same lingering hamstring issue, however, there has been no estimation of when he could possibly be fully fit again.

"He is not that great. He felt it early but kept playing, apparently. It is a bit of a mystery, actually," Cleary said.

"It is a concern so hopefully, we can get to the bottom of it. It's the same kind of story that we had recently, where it doesn't seem that bad. It's frustrating for him and obviously frustrating for us."

The injury may also rob Martin of appearing in the NSW Blues jersey once again. The setback may cause coach Brad Fittler to pick the likes of Keaon Koloamatangi or Haumole Olakau'atu in his place.