Daniel Sams is set to return to the Sydney Thunder side in their derby fixture against the Sydney Sixers on Wednesday night in Canberra following a break because of concussion. Sams missed the Thunder's last two games after being subbed out of the defeat against the Brisbane Heat under concussion protocols, but has been added to an enlarged 19-man squad for Wednesday's game at Manuka Oval.

"He's tracking really well," Callum Ferguson, the Thunder captain, said. "He felt like he was really good and ready to play within a day or two of copping the head knock, but protocols don't allow that. Obviously his health is the most important thing; not just now but in the long-term future."

Ben Dwarshuis has also been included in the Sixers' 18-man squad after missing the win against the Heat with a groin injury he picked up against the Perth Scorchers, though stand-in captain Daniel Hughes said that he was a doubt for Wednesday's fixture.

"I think tomorrow might be a bit of a stretch but we're not sure yet," Hughes said. "He's probably more likely to be ready for the game on Saturday against the Scorchers."

Meanwhile, the Heat have applied to add Morne Morkel to their squad ahead of Thursday's game against the Melbourne Renegades, but have lost Mujeeb Ur Rahman to international duty earlier than expected.

They had hoped Mujeeb would be available for the Renegades fixture before flying to the UAE ahead of Afghanistan's series against Ireland, but a change in travel plans means that he has played his final game of the BBL season.

"Unfortunately, he had to leave a little sooner than we had both anticipated and we will miss him," Darren Lehmann, the Heat head coach, said. "But he has been excellent, and we wish him all the best with representing his country and for his cricket this year."

Morkel, a Sydney resident, signed a deal to play as a local in this season's BBL but is yet to make an appearance after a prolonged period of rehabilitation following an ankle injury. Joe Denly has been cleared of a fracture after dislocating his finger against the Sixers.

For the Renegades, leading run-scorer Shaun Marsh will return to the side after missing two games when he went on paternity leave. English allrounder Benny Howell could return to the squad with Mohammad Nabi on international duty and Rilee Rossouw injured, though coach Michael Klinger hinted that he would prioritise giving opportunities to young players with qualification for the finals in jeopardy.

"Getting games into these guys now is going to develop them even quicker," Klinger said. "With the injury to Rilee Rossouw and now with Nabi being away, these guys are going to keep getting opportunities. If they can be involved in winning teams it's going to be huge for them."

Thursday night's game will be the first of the season staged in Melbourne. Victorian public health officials have capped attendance at 15,000 for games in the city, at both the MCG and Docklands Stadium.

Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98