Perth Scorchers opener Jason Roy is in severe doubt to take his place in Saturday night's BBL final against the Sydney Sixers with him needing to pass a final-minute fitness test prior to the toss.

Roy was withdrawn from the Challenger against Brisbane Heat on Thursday night after injuring his ankle at training during the week when he went over on it during a warm-up game at training in unusual circumstances.

Cameron Bancroft replaced him at the top of the order and made an unbeaten half-century in a rollicking 114-run opening stand with Liam Livingstone which set-up the Scorchers' comfortable win.

Scorchers captain Ashton Turner said Roy has barely tested the ankle since the injury and would need to do so before being declared fit to play.

"He hasn't been put through many physical tasks," Turner said. "I think the call was made pretty early that he'd miss the last game. I know he'll do a fitness test before the game tomorrow and I think he's waiting as eagerly as I am to see how much he can move and what his restrictions are. On the back of not being able to really test it, I don't think anyone has a great idea of the chances of him playing.

"It was pretty innocuous. I wish it was on film because he would have looked like a bit of a clown. He was changing direction with no balls around him, no other people around him and he just went over on his ankle. It was one of those, sort of, freak incidents.

"At the time no one really knew what was happening. It's unfortunate for him. He's been such an important part of our team and like most superstars of international cricket they love playing in big games and they pride themselves on their performances in big games. I know he was shattered to not be able to take his place in the XI."

Turner said it was a luxury to be able to bring in Bancroft at short notice and have him perform like he did, considering he had batted just five times in the tournament prior to the Challenger and had not opened in a T20 game for more than two seasons.

"It's a nice position to be in for me where I'm not too stressed either way," Turner said. "We'd love to have [Jason] come back. He's been brilliant for us in this tournament. But should he not pull up and be able to take his place in the XI, to have Cam Bancroft, who has shown over a number of years that he's capable of playing match-winning innings as he did last night., we're very fortunate to be in that position."

The Scorchers and Sixers will meet for the fourth time in a BBL final and the fourth time this season. The two teams have developed a healthy rivalry in the 10 editions of the tournament.

The ending to the Qualifier in Canberra last Saturday, where Andrew Tye bowled a wide which denied James Vince the chance at a century, has the potential to add extra spice to the final but Turner was not convinced.

"I'll say yes so you can write about and create some more hype and gets some more eyeballs on the articles," Turner said. "I think that there are so many different factors that come into creating tension in a game. There's probably no more motivation than being able to lift a trophy to incentivise playing well.

"I said this on the night of that game that anyone who knows AJ Tye knows that he plays the game in the best spirit. That was an unfortunate end to the game and I said on that night I hope it didn't take away or detract from how well James Vince played. He was brilliant that night and that being said, to watch AJ bowl last night, he was back to his best."

It has been a remarkable turnaround for the Scorchers after starting the season without a win in their first four games. There was some pressure on coach Adam Voges after the winless start but Turner believes his calming influence has played a big part in their turnaround in form.

"We knew it was a long season, 14 games, and we knew we were too good a team to keep losing," Turner said. "Our fortunes were going to turn eventually and thankfully for our coach's sake, we were able to take some of the heat off him. He's been brilliant throughout the tournament.

:The consistency from when we're losing to when we're winning, the preparation has remained the same. Vogesy has been so level-headed throughout a long tournament that we feel as players we've been able to pay him respect by winning games and hopefully we can give a trophy to lift tomorrow night."