The left-arm orthodox spinner will play a crucial role in Sunday's semi-final against Wests/UC at Stirling Oval.

Defending title-holder Albury Wodonga will face Queanbeyan in the other semi-final at Kippax, with the winners to square off in the grand final under lights at Manuka Oval on Sunday night.

Devoy has been in career-best form for Tuggeranong and the Comets. He claimed a nine-wicket haul in a Futures League innings late last year and is the leading wicket-taker in the Cricket ACT first-grade competition.

Having seen slow bowlers reign in the Twenty20 Big Bash, Barrington-Smith believes Devoy can do a similar job on the new surface at Manuka Oval.

''His four overs will almost determine the game for us,'' Barrington-Smith said. ''His batting is also really handy at the top of the order.

''We've got a few older blokes in the team, so we're probably better suited to the Twenty20 format.''

Wests/UC is the only one of the four teams left in the race yet to get its name on the trophy.

Tuggeranong claimed the inaugural title in 2010-11, with Queanbeyan and Albury Wodonga successful in the past two years.

Wests/UC stand-in skipper Ethan Bartlett dismissed rumours regular captain Ben Oakley would return from BBL duties with the Adelaide Strikers to be a late inclusion.

They are also without young gun Matthew Condon, who made a hundred on Friday for the ACT at the national under-17 championships in Adelaide.

''We've still got a pretty good bowling attack, so we'll be looking to Dale Riley and our spinners to cover for Ben not being there,'' Bartlett said. ''Devoy's a quality bowler, but you can't afford to see anyone off in a Twenty20 game.''

Queanbeyan will be without one Dean but will regain another for the semi-final.

Leg-spinning all-rounder Blake Dean returns from his stint with the Sydney Thunder to captain the side, while Jono Dean remains with the Adelaide Strikers after smashing 29 off just 15 balls in his BBL debut on Thursday night.

A full round of the John Gallop Cup one-day competition will be played on Saturday.

■ SATURDAY

John Gallop Cup: Eastlake v ANU at Kingston Oval; Weston Creek Molonglo v Tuggeranong Valley at Stirling; Ginninderra v Wests/UC at Kippax; Queanbeyan v North Canberra Gungahlin at Freebody.

■ SUNDAY

Konica Minolta Twenty20: Semi-finals: Wests/UC v Tuggeranong at Stirling, 11am. Albury Wodonga v Queanbeyan at Kippax, 11am. Grand final: Winners of the two semi-finals at 7pm at Manuka Oval.