The back-to-back MLS champions meet Monterrey in the semi-final first leg at The Home Depot Center on Wednesday night with Keane expected to play despite injuring his calf on international with Republic of Ireland last week.
"It feels fine at the moment. I trained yesterday and today and I'm ready to go tomorrow," said Kean on Tuesday.
"In your head, you always believe you're going to be ready. But until you actually do some running. I came in Sunday myself to do some stuff with the physio and did some running on the field.
"Once I got through that running, I knew I was going to be ready for this game. But in the back of my mind, I kind of thought I was going to be ready [all along]. But you never know.
"Once I'm playing, I'm playing. Once I start, I'll be ready to go [for 90 minutes]."