The number seven was originally named to face the Cowboys in what would have been his first hit-out for the year after missing the club's draw with the Gold Coast Titans last weekend.
Instead, he woke up with back stiffness after training on Tuesday at Twin Waters - a session he got through, including extras - without incident, according to coach Kevin Walters.
"Adam ran well yesterday including some extras but is a bit tight in his back this morning so he won't train today at the main session, which will mean he won't play against the Cowboys," Walters told the media.
"We want him cherry ripe for Round 1 and he's moving really well after a big pre-season, so there's no use taking a risk with him in a trial game in these circumstances."
Reynolds spent some time on the sidelines during his first season at Red Hill last year, playing 20 game out of a possible 24 for the club.
It was the least amount of games he has played in a single season since 2016, when he played 16. He has managed more than 20 in every season since, with 25 being played in 2021.
The former Tiger will serve as the primary back-up option to Reynolds this year, and would be favoured to start in the opening round of the season should Reynolds be passed as unfit.
It's understood that, providing there are no further setbacks however, Reynolds will likely be fit to take on the Penrith Panthers in Brisbane's season-opener on Friday, March 3.
Madden himself has spoken on the prospect of switching to number six and fighting young gun Ezra Mam to be Reynolds' halves partner, suggesting he did not move to Red Hill to run around in the QLD Cup.
The Broncos' trial against the Cowboys will be played on the Sunshine Coast, with kick-off set for 8:55pm (AEDT) on Saturday evening.