The 26-year-old Greek forward suffered a hyperextended left knee last week in a playoff loss to Atlanta and missed Milwaukee's past two games, both wins to reach the team's first NBA Finals since 1974.
"We have a lot of confidence he's going to be able to impact winning in a positive way whenever he plays," Bucks coach Mike Budenholzer said in a pre-game meeting with reporters.
"I know he will give us 100% of what he can give. That's all you can ask from anybody."
Budenholzer said the Greek standout had made progress over the past two days and was upgraded officially from doubtful to questionable Tuesday afternoon.
Phoenix Suns coach Monty Williams said his team was ready for the Bucks whether or not Antetokounmpo played.
"I think you will see multiple guys on Giannis, if he does play. We're prepared for either situation," said Williams.
"No one has been able to stop him, but you don't want to give him everything.
"He's a decorated, All-World player, so we know it's going to take our team defense to try to nullify what he does effectively.
"We have to remember who we are and establish the floor with that."