The Knights have named the 23-year-old as Lachlan Fitzgibbon's injury replacement in the second row for Saturday's elimination clash against the Warriors.
It's the Knights' first semi-final since 2013 and only Lucas' seventh first-grade appearance, making him by far the least-experienced player taking the field in Auckland.
Lucas may not have been the Knights' first choice for the crunch clash, but he's proven adept at stepping into pressure situations this year.
He made his NRL debut following a bloodbath of a round-two win over Wests Tigers at Leichhardt Oval.
Knights players dropped like flies that afternoon, with Jayden Brailey (concussion), Tyson Frizell, Jack Johns (ankle injuries) and Jacob Saifiti (send-off) forced from the field.
Most significantly, Kalyn Ponga was taken off following the latest in a string of head knocks.
The carnage forced the Knights to name three NRL debutants on the bench for their next game, one of whom was Lucas.
Lucas' elation at making his debut came as the Knights began the process to determine whether their star player would ever take the field again.
"It was a weird week," Lucas told AAP.
"But obviously a very special one for me. I don't think the club made us feel (uncomfortable about Ponga's concussion) as a playing group. I thought that it was all handled very well."
As the Knights' top-eight push intensified, they again called on Lucas, who scored a try against Cronulla in round 26 to help confirm a return to finals.
Lucas' latest SOS call comes with the highest stakes yet; a preliminary final spot is up for grabs at Mount Smart Stadium.
"Obviously there's going to be a lot of emotions there and a lot of nerves," Lucas said.
"But if I just stick to my processes that I've been doing all year, that's all I can do."
The finals debut comes after years of patience from Lucas, who relocated from the NSW South Coast as an 18-year-old to pursue his dream with the Knights.
He knew no one in Newcastle, watched on as new mates such as Bradman Best, Phoenix Crossland and Mat Croker debuted before him, and only earned his first top-30 contract this year.
Lucas' father grabbed a last-minute ticket to Auckland and will cheer him on among a packed house of Warriors fans.
"It's a great story," coach Adam O'Brien said.
"He's a young kid, a couple of years ago just on a train-and-trial type deal, who's just worked his backside off.Â
"He's exactly what we want to be as a footy team. He's fit, tough, competitive."
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