England winger Tom Johnstone will see a specialist to assess ongoing concussion-related symptoms.
The Wakefield back was withdrawn with a head knock in the round two defeat by Wigan, and has yet to return to the Trinity starting side since.
It’s a cruel twist of fate for Johnstone, who has missed a great number of games with knee ligament injuries in the past two seasons.
“It doesn’t look great to be honest,” Chester told BBC Radio Leeds.
“He’s going to see a neurosurgeon, he’s still got symptoms, he’s still getting headaches after all this time.
“We put him on a bike a few days ago and straight away he got some headaches. We’ve just got to try to get him through this tough period that he’s going through at the minute.
“We’ve got a lot of good staff here and Stu (Dickens) in player welfare is working with him pretty closely, but at the moment we’re being led by people more intelligent than me.”
Though Chester is uncertain about the timeframe of a return, the winger will be unavailable for a month at minimum.
While Chester admits he does not know what the specialists will say about any timetable for a return, Johnstone will remain unavailable for “a minimum four weeks at least”.
“There are some real strict guidelines around it (concussion and head/brain injuries),” Chester added.
“It’s a case of ‘how long is a piece of string?’, which is tough on Tom.
“Fingers crossed we get good news on Monday.
“Tom is really down, disappointed and going through a tough spell but we’re pretty sure he’ll come through the other side.”