Trbojevic suffered a Grade 2 hamstring strain at training in December with a two-month recovery period expected.
The star fullback was otherwise progressing well from shoulder surgery that cut his 2022 season short and remains on track for the season opener against the Bulldogs on March 4.
Papenhuyzen, meanwhile, has been sidelined since picking up a knee injury against Canberra in July, and will look to return from the United States in time for the second week of Melbourne's annual pre-season camp in Geelong.
Meanwhile, Bulldogs five-eighth Matt Burton underwent minor ankle surgery following his return from the World Cup but will return to full training in January.
Broncos forward Kobe Hetherington is "out for an extended period" after he ruptured his biceps during a training session in December. Hetherington underwent surgery immediately and will aim to return to the field in the middle of 2023.