Perth Scorchers spinner Ashton Agar will not play in the BBL regular season as he continues to battle with his recovery from a calf injury.

Ashton Turner will also captain the Scorchers for the remainder of the season after Mitchell Marsh opted out of the captaincy duties in the week leading up to the tournament.

Agar suffered his calf injury while batting in Australia's third ODI against India in Canberra in early December. The injury saw him ruled out of the T20I series that followed.

He has not played since due to ongoing issues with his calf with his recovery taking longer than was initially expected. He is now set to be unavailable until the end of January.

"Ash has been experiencing ongoing soreness during rehabilitation from the right calf injury that he sustained playing for Australia," WACA Sports Science Manager Nick Jones said. "This injury will require a more extended period of rehabilitation and we hope Ash will be ready to return to play in approximately one month's time."

Meanwhile, Marsh spoke to the Scorchers hierarchy a week prior to the tournament requesting that he not captain the side for the BBL. He was recovering from an ankle injury in the lead-up to the tournament but he has played in all five of the Scorchers matches so far and has bowled in the last two.

The Scorchers handed the captaincy to Turner and he will remain in the role for the remainder of the tournament. Turner had led the Scorchers previously in Marsh's absence and captained Western Australia to the Australian domestic 50-over title last summer while Marsh was injured with a broken hand.