The openside flanker lines up against the Dragons Premiership Select side in today’s British & Irish Cup tie near Caerphilly in Glamorgan.
It has taken Bainbridge a while to rack up his half-ton, this being his fourth season having debuted as an 18-year-old against Doncaster Knights in 2014.
“I’ve had my ups and downs along the way,” said the ex-England Under-20s international.
“There’s been some injuries and things, but just to get to 50 itself is a pretty good achievement.
“It is my first milestone reached with Carnegie and hopefully there’ll be plenty more to come here.”
Fans will certainly hope that rings true as plenty of Bainbridge’s peers, like Jack Walker, Paul Hill and Lewis Boyce, have instead left to make the move up to the Premiership.
The high regard that is held for Bainbridge was shown when head coach James Lowes made the 21-year-old his captain for last week’s 43-22 B&I Cup win against Dragons Premiership Select at Huddersfield YMCA.
“It was a bit overwhelming when I was first asked as there was a lot more older and experienced players than me,” said the Middlesbrough-born flanker.
“But, at the same time, I did really enjoy it and we won, which made it all the more enjoyable.”
Meanwhile, Rotherham Titans have signed centre/fly-half Rory Jennings and prop Sam Nixon – both 21 – from Bath to ease their injury problems.
They come straight into the squad today as they visit Championship rivals Ealing Trailfinders in the B&I Cup.
Doncaster see the welcome return of Paul Jarvis, the gifted full-back who has been sidelined since being injured in the season opener back in September.
They head to Wales to face a Cardiff Blues Select XV at Sardis Road. Hooker David Nelson is fit after a broken hand and Jack Ram also returns after injury.
Also, New Zealander lock/back-row Adam Batt has signed until the end of the season after a successful trial period.