CONFIRMED: Donald's Ulster move halted
Donald, who has been targeted as the ideal replacement for Australian Christian Leali'ifano, should have joined the side on a short-term contract after his commitments in Japan concluded.
However, a recent injury sustained during the final match of the season for Japanese side Brave Lupus has made it impossible for the 34-year-old World Cup winner to move to Belfast.
The injury will see him out of action for more than four weeks.
The province Ulster released a statement.
"Ulster Rugby is not in a position to proceed with the signing of Stephen Donald, after receiving a medical report on the player on Sunday," the statement read.
It further explained: "Stephen had agreed on a short-term deal to join the Province, but he sustained an injury while representing his club in the final game of the Japanese season, which will rule him out for more than four weeks.
"The timeline now makes it very difficult to find a suitable replacement, but we will continue to monitor the market,"