Darren Sammy said Gayle would not be missing the knock-out tie ???at any cost??? but admitted the injury remains a concern for the opening batsman.
Gayle, who was rested for his side’s final pool game against United Arab Emirates because of the same problem, has been undergoing treatment ahead of the match in Wellington.
All-rounder Sammy said: “He had a scan. He had an injection. Chris is not missing this quarter-final for anybody. He is more pumped up for this than the rest of the team.
“It’s just unfortunate his back keeps hindering his progress but he won’t miss the quarter-final.”
Sammy admitted his team were underdogs but reminded the press conference that shocks can happen, referring to a major surprise in the world of boxing 25 years ago.
Sammy added: “It’s a big match but I remember some guy named Buster Douglas beating Mike Tyson so it’s the case of that on Saturday. ?? ?? ?? ??
“It’s the business end so you can win all your pool matches but come the knockout there is no guarantee you will win.??
“You turn up on the day and the guys know what is at stake and we are doing everything in our powers to beat Mike Tyson. ?? ??
“We’re not supposed to be here, we have not played our best cricket, we have been so inconsistent but we are still in the quarter-finals.
“If we put all the good things we know we can do right, then no team will beat us. And the other teams know that as well.”