Kane Williamson has become the latest overseas player to pull out of the Hundred, withdrawing from his £80,000 (US$110,000) contract at Birmingham Phoenix while he manages his elbow injury.

Williamson, New Zealand's captain, has been managing the injury for the past six months, missing an ODI series against Bangladesh, the start of the IPL and the second Test against England with the same problem. He is still in the UK following the World Test Championship final and is expected to be involved with the Edgbaston-based team in a mentoring capacity.

Finn Allen, his compatriot, has been lined up by Phoenix as a replacement and will stay in the UK following his stint in the Vitality Blast with Lancashire. Allen, who has the highest career strike rate of all time in T20 cricket, has scored 215 runs in his eight innings for Lancashire, averaging 30.71 with a strike rate of 138.70.

Shaheen Shah Afridi has also withdrawn from his Phoenix contract due to his international commitments with Pakistan, who tour the Caribbean during the Hundred's window from July 21-August 21. Adam Zampa, their third men's overseas player, is also expected to pull out as he is part of the Australia squad for their limited-overs tours to the Caribbean and Bangladesh.

Meanwhile, Lungi Ngidi is set to join Welsh Fire. Ngidi, the South African fast bowler, is likely to be available for five games following their limited-overs tour to Ireland as a replacement for Jhye Richardson. Jimmy Neesham, the New Zealand allrounder who has been playing for Essex in the Blast, is expected to fill in for the start of the tournament.

With Kieron Pollard also expected to miss at least the start of the tournament due to his international commitments as West Indies' captain in their T20I series against Australia and Pakistan, ESPNcricinfo understands Glenn Phillips, the New Zealand batter who has been playing for Gloucestershire in the Blast, has been lined up as a potential replacement.

Elsewhere, Wahab Riaz, the Pakistan left-arm seamer, is understood to have been lined up by Trent Rockets as a replacement for Nathan Coulter-Nile, the Australian allrounder. Riaz has not played a T20I for Pakistan since December and is available after missing out on their squad to play West Indies in the Caribbean. He was the second-highest wicket-taker in the PSL this season.

Coulter-Nile and Richardson are the latest Australians to pull out, with a mandatory 14-day quarantine period on return and the tours to the Caribbean and Bangladesh a major factor in the various withdrawals. Teams are braced for further withdrawals in the coming days with the pressures of a packed international schedule and the difficulties of travel in the time of Covid combining to squeeze the availability of the world's top players.

The Hundred's wildcard draft will take place on Friday, with each of the men's teams picking one unsigned domestic player on the back of their performances in the Blast so far this season. Jordan Thompson, Sam Hain and Sam Cook have all attracted interest.

Matt Roller is an assistant editor at ESPNcricinfo. @mroller98