"Hopefully soon. I don't know," he said.
Willis threw a bullpen session on Wednesday and has been playing catch.
"I'm just trying to catch up," he said. "I feel good. I feel like my strength is getting back, so that's good."
The Phillies released Willis on Friday.
"It's just about getting the strength back and the timing back," he said. "That's why I want to get in games. You can't teach that, game speed, so I want to get back in games, whether it's minor league games or big league games. I just want to start pitching and get back as quickly as possible, especially with a new (role)."
Willis is being converted to a left-handed relief specialist.