The Newcastle Knights will be left sweating on a trio of injuries ahead of their trip to Las Vegas to open the NRL season against the North Queensland Cowboys.

Young forwards Jermaine McEwen and Cody Hopwood were both withdrawn from Saturday evening's opening trial match against the St George Illawarra Dragons, while Dane Gagai was also a non-starter.

Justin Holbrook revealed McEwen and Hopwood have minor niggles and should be available to return for the Knights' second pre-season challenge match next Saturday against the Canterbury Bulldogs at home, with kick-off set for 6pm (AEDT).

Gagai's injury was always set to leave him sidelined for the club's opening trial, but there are now concerns he will miss next weekend as well. He was expected to be named in the All Stars squad, but was overlooked when teams were named in recent days.

"Cody Hopwood and Jermaine McEwen unfortunately picked up some injuries late in the week," Holbrook said per NRL.com.

"They're two that were really impressive in pre-season but didn't get the run today.

"Cody hurt his calf and Jermaine hurt his ankle. They're only minor, they both should be right this week.

"With Gags it's just a slight hammy he just did at training."

Hopwood, a talented young prop, would have been an unlikely starter for the Knights in the opening round, however, McEwen was seen as a good chance of taking the vacant second-row spot following the departure of Englishman Kai Pearce-Paul, who has joined the Wests Tigers for 2026 and beyond.

McEwen, who played 17 games last year, is likely in a race for the spot against the versatile Thomas Cant, and more experienced Brodie Jones, both of whom played against the Dragons.

Gagai is likely to hold onto his centre spot for 2026, with the Knights backline still having plenty of questions over it, including whether Fletcher Sharpe will feature in the halves, or in the outside backs.

The Knights season opener will be played at 1:15pm (AEDT) on Sunday, March 1 (Saturday, February 28 local time) against the Cowboys in Las Vegas.