Wade, the only wicketkeeper in the squad, is the second Australian cricketer after leg-spinner Zampa to have tested positive on Wednesday evening.
"An incredibly freak accident to Josh, unfortunately. He's potentially not going to take any part in the World Cup, so that's all to unfold," McDonald said on SEN's Whateley.
Australia and Sri Lanka play three T20Is, followed by five ODIs in Colombo and Pallekele.
The development comes close on the heels of Andrew McDonald's appointment as Australia's head coach.
Andrew McDonald has played four Tests and recently oversaw the Australia's away Test series win against Pakistan.
Andrew McDonald joined Australia’s coaching team in 2019 after leading Victoria state and the Melbourne Renegades to all three domestic competition titles during the 2018-19 season.
McDonald returned last week from the side's successful Pakistan tour where they won the Test series and the sole Twenty20.
Cricket Australia has reportedly found a replacement for Justin Langer and is set to name Andrew McDonald as the new full-time head coach in the coming days.