St George Illawarra Dragons forward Jack de Belin will miss Saturday night's trial against Newcastle with a virus.
The club released a statement as part of their team announcement on Tuesday with coach Paul McGregor indicating the representative star had an "upper respiratory tract infection" and was sent home from training duties.
De Belin's availability for the annual Charity Shield clash will be monitored.
Meanwhile, his New South Wales teammate Angus Crichton is on track to make his Roosters debut in the club's trial against Manly on March 2.
The former South Sydney second-rower travelled to the United Kingdom as part of the Tricolours' 23-man squad, but missed the World Club Challenge as he continued his rehabilitation from off-season shoulder surgery.
"A couple of weeks ago we knew he wasn’t going to play and now the focus is getting right for the Manly trial," Roosters coach Trent Robinson said.
Cronulla's Matt Moylan and Jayson Bukuya are on track to feature in at least one of the club's trials over the next month as the Sharks look to build on their new-look spine for 2019.
The pair both underwent shoulder surgeries in the off-season along with Josh Dugan, who isn't tracking as well as his teammates.
NRL.com understands Dugan is rated no chance of playing in the pre-season fixtures as he remains on limited duties.
The latest Telstra Premiership injury news:
Playmaker Anthony Milford suffered a minor hamstring injury at training and is in doubt for the club's final trial game against the Titans on March 2.
Milford also underwent a shoulder reconstruction over the pre-season but the Broncos remain confident he will be fit for round one.
Joe Ofahengaue was cleared of serious injury after suffering rolling his ankle at training in January.
Andrew McCullough (finger), David Fifita (ankle), Payne Haas (shoulder), Matt Gillett (shoulder), Jack Bird (sternum) and Jaydn Su'A (ankle) all nursed injuries over the pre-season but are available for the trials.
Raiders centre Joey Leilua suffered a minor hamstring injury at training in early February and was ruled out of the club's trial against the Bulldogs in Bega on February 23.
English recruit John Bateman (side strain) and Michael Oldfield (groin) were also ruled out of the pre-season clash with minor injuries but are expected to be available for round one.
Jarrod Croker (knee) and Aidan Sezer (hamstring) have made full recoveries and were selected for the trials.
Jordan Rapana will miss the first 11-14 rounds of the 2019 season following surgery on a dislocated shoulder suffered on Kiwis duty. Ata Hingano is also expected to miss the opening six months of the season with a similar setback.
Josh Jackson (shoulder), Kieran Foran (hamstring) and Marcelo Montoya (hamstring) have all been named in the club's trial against Canberra in Bega after off-season injuries.
Both Jackson and Kerrod Holland (ankle) were well ahead of schedule following surgeries.
Adam Elliott (wrist) and Corey Harawira-Naera (groin) pulled up well from the All-Stars clash and were also included in Dean Pay's squad for the pre-season fixture.
Bulldogs utility Fa'amanu Brown had surgery before Christmas for a leg stress fracture. He'll complete rehabilitation in February with an aim to return by round four.
Matt Moylan, Jayson Bukuya and Josh Dugan all underwent shoulder operations in the off-season.
Moylan and Bukuya will miss the club's first trial on February 23 but could feature in the final pre-season hit-out in Maitland against Newcastle.
Dugan remains on light duties and is a better chance at playing in round one than getting any minutes in the trials.
Sharks forward Wade Graham is targeting a comeback from his torn ACL "between round 9 and 12" in 2019.
The NSW and Australia back-rower told NRL.com he was no chance of being fit for the start of the season. "That's the timeframe I'm looking at - between round nine and 12," Graham said. "It's one of those things you can't rush. I'm going to make sure it's 100% right before I come back."
Jack Williams (pectoral) returned to training before Christmas and is available for the club's trials.
Ryan James missed the Harvey Norman All Stars game with a medial ligament injury and is in doubt for the season opener against the Raiders.
James was initially expected to miss two to three weeks, but he's now touch and go for the trials and round one.
Storm recruit Ryley Jacks had minor elbow surgery in late January but should feature for the club's final trial in March against the Broncos.
AJ Brimson is also targeting a return in that clash after undergoing a shoulder reconstruction in September.
Lachlan Croker and Curtis Sironen joined their teammates for training in November after more than six months off with ACL injuries.
Apisai Koroisau is also working his way back into shape in the off-season after missing the final three months of the competition with a fractured foot.
The trio should be available for the club's opening trial against Cronulla at Shark Park on February 23.
Nelson Asofa-Solomona returned to training in December following an ankle injury and has been included in the club's first trial against the Warriors in Geelong.
Michael Morgan is available for the club's first trial against the Titans on the Sunshine Coast after a four-month injury layoff with a biceps injury.
Cowboys veteran Matt Scott had neck surgery last year but is back into full contact with an eye on getting some game time in the trials.
Given the flood crisis that hit Townsville in February, Cowboys coach Paul Green told reporters he may need to play more of his top side in the first trial in a bid to play catch up after two weeks of training disruption due to flooding.
Knights centre Tautau Moga is set for a stint in the Intrust Super Premiership for the opening round of the season as part of his return from an ACL injury.
Knights coach Nathan Brown confirmed Moga was improving at a "rapid rate" but would not be rushed back into the round one NRL side.
"He’s going to start doing a little bit more stuff with the team. (We're) not expecting Tau to play until Round 1," Brown said.
"That day, he’ll probably look to play half an hour in reserve grade."
A possible replacement for Moga, new recruit Hymel Hunt, suffered a hamstring strain before the club's first trial against St George Illawarra and is in doubt for round one.
It's a similar situation for prop Jacob Saifiti, who broke his leg in December following a pub altercation, with Brown indicating he'll miss the trials but be pushing for a spot in round one.
Injured Knights hooker Slade Griffin has started running in another step towards playing again.
Kalyn Ponga (ankle), Connor Watson (groin), Nathan Ross (groin) and Daniel Saifiti (foot) were all named for the first trial against St George Illawarra in Kogarah on February 23 following surgeries.
New signing Blake Ferguson is available for the club's main trial game against Penrith after recovering from a broken leg and nasty leg cut over the summer break.
Nathan Brown spent six weeks on the sidelines with the rehabilitation group after undergoing knee surgery in late December but has since returned to the field in time for the pre-season fixtures.
Manu Ma'u (cheekbone/shoulder) commenced contact training in January after multiple surgeries in the off-season and is also eyeing a return in the Penrith trial.
Daniel Alvaro (knee), Peni Terepo (hamstring) and Josh Hoffman (shoulder) all played in the pre-season trial against Canberra on February 15.
Will Smith (hamstring) and Kaysa Pritchard (shoulder) remain on track for round one returns.
Dallin Watene-Zelezniak had knee surgery following the Kiwis' tour of the UK and was not included in the club's first trial against South Sydney at Redfern on February 23.
Nathan Cleary (ankle) was also not included in the trial squad as he continues his return from surgery in the off-season.
Reagan Campbell-Gillard (jaw) and James Maloney (neck) were named for the clash.
Sam McKendry continues to come back from a third ACL reconstruction and remains on limited duties.
Greg Inglis will monitor his knee throughout the 2019 season after revealing the ACL injury he suffered two years ago is hindering his ability to train.
There are fears Inglis will miss the trials and early rounds of the season but a recent club update did not confirm the reports.
"He's got a bit of fluid on his knee, which we're managing," Rabbitohs physiotherapist Luke Annesley told rabbitohs.com.au.
"We're not concerned about it at all. We'll continue to work hard with him in the gym and then build his running up in the coming weeks."
Inglis was left out of the club's first trial against Penrith but there was better news around Sam Burgess (shoulder/wrist), Cameron Murray and Campbell Graham (both shoulder), with the trio all named for the clash.
Adam Doueihi underwent an ACL reconstruction in August. He started light running prior to the Christmas break with the club in no rush to push for a return in the early stages of next season given his young age.
Dean Britt (groin) is back running in a slow return from a lengthy groin complaint.
Gareth Widdop (shoulder), Tariq Sims (knee), Paul Vaughan (foot) and Jacob Host (shoulder) were all named for the club's pre-season trial against the Knights.
Jack de Belin was ruled out of the clash with a virus. His availability for the charity shield in Mudgee is yet to be determined.
James Graham and Tyson Frizell have been rested for the game, while former Bronco Jonus Pearson is unavailable for personal reasons.
Angus Crichton (shoulder) missed the World Club Challenge but is aiming to return in the team's trial against Manly on March 2.
English recruit Ryan Hall travelled over to the UK with his new teammates but continues to rehabilitate an ACL injury.
Roosters five-eighth Luke Keary, who was sporting a moonboot over the Australia Day weekend, returned in the win against Wigan.
Blake Green is set to miss both pre-season trial games with a hamstring injury but is aiming to be fit for the opening round of the season.
Hooker Issac Luke is in doubt for the start of the season as he recovers from shoulder surgery. The New Zealand international is expected to start contact training at the end of January, with his return to action to be determined after that.
Warriors captain Roger Tuivasa-Sheck (knee) and Nathaniel Roache (back) are both available for the trials with Roache to play the Storm after 18 months on the sidelines.
Moses Mbye is expected to be fit to play in the Wests Tigers' second trial against the Warriors in New Zealand on March 2 after suffering a knee injury at training.
Benji Marshall is also expected to be fit for that match after recovering from a minor hamstring tear.
Luke Brooks had stitches inserted at the base of his nose after a training accident in February but isn't expected to miss any game time.
Josh Reynolds (hamstring), Josh Aloiai and Robbie Rochow (both hand) are all available for the pre-season fixtures.