Kiwis star Benji Marshall at a family reunion in Porirua in 2010 with his grandfather, Toby.

Wests Tigers co-captain Benji Marshall will play one of the most emotional matches of his NRL career on Friday after the death of his 93-year-old grandfather, Toby, in New Zealand.

Marshall was granted personal leave this week to say his farewell in his home country, but has been declared a certain starter to take on Newcastle.

"He missed the one session which is not unusual for Benji anyway. He was back for our main session yesterday," Cleary said on Thursday.

Marshall, who will head back across the Tasman after the match for the funeral on Saturday, considered his grandfather his No 1 fan.

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In a Facebook post on Wednesday night, Marshall wrote: "Rest in love my Koro, no more pain and suffering after 93 years of life. As much as it hurts to lose you today you are in a much better place now.

PHIL REID/STUFF Benji Marshall with his grandfather Toby in 2010.

"I lived with you since the day I was born and learnt so much from you over the years. You were my number 1 supporter and always had my back."

Cleary said it was important Marshall was given the chance to be with his family, adding the 33-year-old was in good spirits upon his return with the playing group.

"I think he's alright. It was good for him to get the opportunity to go back and say his farewell. We had a good chat yesterday and he seemed his bright self," Cleary said.

GETTY IMAGES Benji Marshall is back from New Zealand for the Tigers' must-win game against the Knights on Friday.

Marshall's long-term future remains undecided as he and fellow Tigers veteran Robbie Farah weigh up whether to stave off retirement for another season.

Cleary said there was value in having both players kick on in 2019.

"I'd love them to play next year. Benj and Robbie have had such long, distinguished careers. Certainly at this club, what they've done has been enormous," he said.

GETTY IMAGES Benji Marshall's Tigers are four points behind the Warriors in ninth place on the NRL ladder.

"And they're still playing well.

"But it's one of those things where it's just that time in their careers where they've got to be sure that they want to go around and we've got to be able to make it work as well."

Cleary will lean on both when they hope to keep their finals dream alive with a win over the Knights at McDonald Jones Stadium on Friday.

The ninth-placed Tigers, who blew a chance to beat Canterbury last week, are four points behind the eighth-placed Warriors with just five games remaining in the season.

"That's what you want from your senior players and guys with leadership - we all need that. Those guys hurt probably more than the younger guys on nights like last week," Cleary said.

The Knights missed their shot at three consecutive wins for the first time this year when they lost to North Queensland last week, but get Connor Watson back from injury.

AT A GLANCE

​* Five of the past seven clashes have been decided by single digits.

* The Knights are looking for a third straight win at home for the first time in almost five years.

* Shaun Kenny-Dowall will play his 250th match.