The 30-year-old missed England's opening two games in Perth and Adelaide but is available for the final warm-up game against a Cricket Australia XI starting on Wednesday.
"I am good. It's just a slight strain on my side from throwing," Moeen told reporters on Monday.
"It was a bit frustrating but also not a bad thing, you get a lot more work done.
"I feel like I am ready to play and I can’t wait to spend time in the field. We have got four days of cricket ahead. I can get a bit of game time in my system and then be ready to play, hopefully, at the Gabba."
It will be England's last game before the Ashes series opener in Brisbane on Nov. 23.
England are on a 31-year winless streak in Brisbane but Moeen believes it is important for the visitors to set the marker for the rest of the campaign.
"I've heard a lot about Brisbane," said Moeen. "It's something you have to block out. You have to focus on your game and the situation that the team is in.
"I'm prepared the best I can. When you're out there you rely on your instincts. I know it will be tough, but I've always backed my ability."
England head into the final tour match on the back of a convincing 192-run victory over a Cricket Australia XI in a day-night game in Adelaide.
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