Despite pulling out of the West Indies squad for the forthcoming Test series against South Africa, Chris Gayle will turn out for his South African franchise, the Lions, in Sunday's Ram Slam T20 competition playoff and, if they win, next week's final.

Gayle sustained a back injury while in South Africa, which will make batting for long periods of time difficult but he should be able to manage the demands of the shortest format. "His back is not holding up very well and I can't see him managing five days. I'm not surprised he has had to pull out of the Tests. Still, he has committed to playing for us in these games," Geoffrey Toyana, the Lions' coach told ESPNcricinfo.

Gayle will be rested for Lions' Wednesday fixture against the Knights, which will determine who will host the playoff. That will bring to three the number of matches Gayle has missed in the Lions' campaign as he has battled with his fitness. Gayle sat out matches against the Cobras and Knights on November 14 and 16, little over two weeks ago, but recovered enough to return.

The extent of Gayle's injury became evident on Sunday in Bloemfontein, where Lions lost to Dolphins. "We were getting into the car to drive back and he was really battling to get in. We could see he was struggling," Toyana said.

He has also battled with bat in hand recently, with scores of 11, 3, 8 and 6 from his last four matches, after making an explosive start to the tournament. Gayle scored the competition's first century, off just 55 balls, in East London, sandwiched between two fifties, one on debut for the Lions. He is the competition's third-highest run-scorer with 242 runs from seven innings at 40.33 and Toyana said he has "had a big impact" on the Lions' change room.

"Although he is quite a quiet guy, he has really made a difference to some of the younger guys with helping out and offering advice, and just in general to the dressing-room morale," Toyana said. "We think he has really enjoyed himself here and that he may want to come back to play for the Lions."

Gayle had previously been linked to another South African franchise, the Dolphins, whom he had signed with in the 2011-12 and 2013-14 seasons. He never played a game for them after injuries kept him out of both campaigns. This time, however, he has been a key member of a Lions' outfit looking to restore glory after trophy-less last summer that gave Toyana second-season blues.

Toyana enjoyed a breakthrough first season in charge, when the Lions shared the 2012-13 one-day cup and won the twenty-over competition, to qualify for the Champions League T20. They are hoping to repeat that this summer but will need victory over the Knights in the playoff to guarantee a top-two finish. Toyana knows that even if they manage that, it is unlikely Gayle will be available for the Lions for the CLT20 but, if he is, "that would be fantastic."

Gayle will leave South Africa after the Lions' campaign ends but may return later in the summer. West Indies are due to play three Tests, three T20s and five ODIs from December 17 before heading to the World Cup.