Vernon Philander has been ruled out of the Bangladesh Test series, as he continues to recover from a lower-back problem with the aim of being fully fit by mid-October. Philander is scheduled to play the fourth and fifth round of first-class matches for his franchise, the Cobras, and will likely play for South Africa in the four-day day-night match against Zimbabwe on Boxing Day.

Philander has mostly recovered from the back niggle he picked up in England, which kept him out of the fourth Test at Old Trafford and has seen him sidelined since. Philander was part of the Cobras pre-season training but has not played any cricket since the England tour.

At an event earlier this week, Philander, who drew criticism recently from former captain Graeme Smith, said he has spoken to captain Faf du Plessis about his fitness. Du Plessis has weighed in on the situation during the England tour, urging the bowler to focus on his fitness.

"It's international sport, you'll always find criticism. As long as it's constructive, then I'm all for it. You've got to take it on the chin," Philander told Independent Media . "Myself and Faf had a good chat afterwards, the way the two of us nailed down things was quite constructive at the end of the day. As long as you're open and honest with each other, that's the key thing. He made his view clear and obviously I made mine clear to him. As long as we understand each other, we've got a road to walk together."

Without Philander, South Africa will rely on Morne Morkel, Kagiso Rabada, Duanne Olivier and Andile Phehlukwayo for the Bangladesh series, with Chris Morris also out injured until mid-October. Morris is expected to return for the T20s against Bangladesh.

Dale Steyn is set for a comeback at the Global T20 in November and joined the South African squad for two days in Potchefstroom, where he worked with team physiotherapist Brandon Jackson and the bowlers in the group.

"Dale has been away from the squad for a while. He still got a few boxes to tick. We wanted him to be around the group again," du Plessis said. "We want to make sure he still feels important because he is a very crucial part of our team and we also wanted him to help out with the younger bowlers."

Firdose Moonda is ESPNcricinfo's South Africa correspondent