Andrew McDonald is set to be the latest big-name withdrawal from the Hundred, amid concerns over fixture clashes and bio-bubble fatigue.

McDonald had been appointed as head coach of Birmingham Phoenix, but ESPNcricinfo understands that he will not be coming to England this summer with his responsibilities as Australia's assistant coach taking priority. Daniel Vettori is believed to be a strong favourite to secure an interim role in charge of the side.

McDonald is instead expected to go on Australia's tour to the Caribbean, which departs in late June and is due to be followed by a trip to Bangladesh in early August. He will remain in contact with Phoenix in a consultancy capacity and is expected to resume his duties in 2022.

McDonald's decision follows a string of other high-profile withdrawals which have included Marcus Stoinis, David Warner and Kagiso Rabada. With fixture congestion (both international and franchise league), quarantine arrangements and bubble fatigue contributing to create something approaching a perfect storm, the ECB is braced for more withdrawals in the coming days. The schedule suggests the involvement of players from the Caribbean and Pakistan may prove especially challenging. New Zealand's players, already in the UK, may well prove the beneficiaries. Lockie Ferguson is expected to replace Rabada for Manchester Originals.

This news is a significant blow to Birmingham Phoenix, though. McDonald had been heavily involved in the planning stages for the tournament, including taking decisions on which players to sign.

George Dobell is a senior correspondent at ESPNcricinfo