The Spaniard is in dispute with the European tour over sanctions they've imposed for him playing in LIV Golf events without obtaining the necessary permissions as a tour member.
Rahm reportedly owes over Stg 2 million ($A3.8 million) in fines but has appealed, a process which was delayed so long he was allowed to play in September's victory in New York.
LIV golfers, including Australian star Elvis Smylie, have all agreed to pay their outstanding fines and commit to playing in more European tour events in order to gain conditional releases to play LIV events.
But Rahm has refused and on Wednesday labelled it as "extortion" from the tour.
Yet Donald hopes to have the two-time major winner in his side again after signing up for a third-straight stint as captain.
"It's the first day on the job so I haven't talked to him yet but obviously I will talk to Jon," said Donald.
"I don't really want to comment as I know he has his own reasons but I look forward to catching up with him and I really hope he is available."
Chief executive of the European Tour group Guy Kinnings said they had followed the rules in place and Rahm's refusal left him with two options.
"It is pretty straightforward: either he withdraws the appeal and settles fines, or he goes to the appeal process - and that is underway - and then go with whatever decision is made in that hearing," he said.
Former USA captains Walter Hagen and Ben Hogan led their team to four and three Ryder Cup wins respectively but neither achieved the three-in-a-row Donald is aiming for at Adare Manor in Ireland.
Donald, the former world No.1, said he had weighed up the pros and cons and, with the support of his family and teammates, was ready to go again.
"I accomplished a great deal with Rome and New York and you obviously do question the possibility of losing if you go again," he added.
"But when you come to the pros there were many more than there were cons and ultimately that is why I am sitting here."
The US hopes Tiger Woods will agree to be captain for the 2027 event, having turned down the opportunity last time out.
"Tiger moves the needle in the game still. Whoever the captain is doesn't really change my role," said Donald.
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