The New Zealand batter Kane Williamson will be playing the T20 World Cup but will be unavailable for the upcoming T20I series against Australia. Earlier he did not play the Test series against Zimbabwe and the following the T20I tri-series. At that time, he was occupied with the T20 Blast tournament, representing Middlesex. He also played two County Championship games and then The Hundred for London Spirit. However, missing the Australia T20I series wasn't in the plan. recently, new Zealnd cricket mandadted all the "casually contracted players" to be available for the T20I World Cup Campaign, which includes this tri-series. Apart from the one against Australia, there are England and West Indies series at home, and later the away series against India and Sri Lanka. One of the casually contracted players, Finn Allen, has been excluded from the Australia series as he is undergoing foot surgery. However, Williamson withdrawing from the series was unexpected. Read also: Australia Beat India by 8 Wickets in 1st ODI at New Chandigarh What is a casual contract? A casual contract is an initiative taken by cricket boards to allow players to be flexible with schedules. As per the norms, players can opt out from certain series due to other commitments, but has to commit fully for major tournaments like World Cups or other important international matches. However, they will receive all facilities from the board as much as the centrally contacted players get. New Zealand cricket was the first one to opt for this, while Kane Williamson and Devon Conway signed this in the 2024-25 season. Recently, New Zealand cricket had released the names of 20 centrally contracted cricketers that excluded five notable names- Kane Williamson, Finn Allen, Lockie Ferguson, and Tim Seifert for the 2025-26 season. They have signed casual contracts, taking up franchise contracts. Allen Siefert and Ferguson are currently having lucrative BBL deals. New Zealand's female cricketer has been casually contracted with the board too, as she has decided to retire from the ODI cricket after the upcoming ODI world Cup. Speaking on casual agreement, NZC CEO Scott Weenink said, "With such a pinnacle event on the horizon we wanted to ensure our best T20 players were ready and available to push for inclusion. The casual agreements are a commitment from the players to NZC and the Black Caps, and in return NZC will offer our full support to these players as part of our high-performance system." He added, "The message from the players is that playing for the Black Caps is hugely important to them and I'm pleased we've been able to agree terms to have them casually contracted for the coming season. Rob [Walter] and the team have a massive period of cricket ahead, home and away, and I know myself along with all of our fans can't wait to follow and support."