Holmes landed awkwardly on the point of his shoulder in a Cameron Murray tackle during the final seconds of the first half of last night's dead rubber State of Origin game at CBus Super Stadium on the Gold Coast.
At the time, Channel 9 broadcaster Ray Warren said it was a similar tackle to the one which has seen Nathan Cleary put on the sidelines for an extended period.
Paul Green then confirmed he wouldn't return during a halftime interview.
It's understood Holmes will go for scans today, and with the Cowboys already battling at the wrong end of the table, they can ill-afford to lose their fullback.
The NRL Physio on Twitter doesn't believe Holmes will miss any more than four weeks however.
Confirmation from the Maroons of an AC joint injury for Valentine Holmes, not expected to require surgery (rarely required for isolated AC joint sprains). Use of sling indicative of a likely grade 2-3 sprain, if confirmed most return within 2-4 weeks (some Gr3’s slightly longer) pic.twitter.com/BmVGBdcphy
— NRL PHYSIO (@nrlphysio) July 14, 2021
If Holmes was to need surgery however, it would rule him out for the remainder of the season.
The Cowboys are currently in 12th place on the competition table, but sit just two points out of the top eight in what is a logjam. Only six points separate 7th and 14th place, with each of the final eight games likely to prove critical in those teams' push to make the finals.
It's a horrid time for North Queensland to lose Holmes, even for a short period of time. While their next two games are both at home in Townsville with opposition clubs forced to fly in and fly out due to COVID protocols, they are set to take on first the Sydney Roosters, then the Melbourne Storm.
Their run home is more comfortable, but with just one win on the road this year, four of their final six will be played away from home, making qualifying for the finals a daunting prospect.