The 20-year-old was handed a short-term contract earlier this month after impressing during a trial spell with the club over the winter and in the opening weeks of the summer.
A product of the Gloucestershire Academy, Russell was released by the Bristol-based club last year but has quickly found a new home at the County Ground.
He has performed well for the second team, and in the recent white-ball matches against the Netherlands national team he ended with impressive figures of seven for 81 across two T20 and one 50-over match.
Now he could get the chance to show what he can do in the Blast.
“It’s great to have Al on board.” said Steelbacks skipper Josh Cobb.
“He bowled at us during the winter at Loughborough and bowled really nicely, so it’s great he’s got his opportunity.
"He brings something into the squad that we haven’t got in a right arm leg-spin option.”
Russell is one of a clutch of young players in the Steelbacks squad, joining left-arm wrist-spinner Freddie Heldreich (20) and James Sales (19), but there is also plenty of experience.
Australian import Chris Lynn will make his club debut at the top of the order, where he will be joined by Ben Curran, who replaces the injured Ricardo Vasconcelos (broken thumb).
“It doesn’t change things too much, obviously we’re all very disappointed for Vasco," said Cobb.
"Being the leading run scorer for us last year, the fact he’s not going to be fit to go from game one is a shame.
“But we’ve got BC (Curran) as a left-hander going in at the top who’s played some valuable knocks for us in the past. He gets an opportunity now so hopefully he takes it.”
New Zealand all-rounder Jimmy Neesham is unavailable for at least the first two matches of the campaign - Steelbacks host Durham on Friday night - and his place will be taken by Australian pace bowler Matt Kelly.
The Bears are skippered by former West Indies star Carlos Brathwaite, and include in their ranks the former Steelbacks opener and prolific Ireland run-maker Paul Stirling.
There is no place for former Northants fast bowler Olly Stone, who remains sidelined with injury.
Steelbacks Squad to face Bears: Josh Cobb (c); Ben Curran; Brandon Glover; Freddie Heldreich; Matt Kelly; Rob Keogh; Chris Lynn; Lewis McManus; Alex Russell; James Sales; Ben Sanderson; Tom Taylor; Graeme White; Saif Zaib
Bears squad: Carlos Brathwaite (C); Chris Benjamin; Jacob Bethell; Danny Briggs; Ethan Brookes; Henry Brookes; Alex Davies; Sam Hain; Olly Hannon-Dalby; Adam Hose; Jake Lintott; Craig Miles; Paul Stirling