The Monster Yamaha Tech 3 rider has not let the injury hamper him, making his best-ever start to a MotoGP season.
"It's still taking it's time, which is frustrating," Smith replied, when asked about the injury.
"We can't find a solution to speed [the healing] up. But when I went for the final diagnosis it was a four to six month injury and I'm only on 10 to 12 weeks."
Smith confirmed to crash.net that he has a torn ligament.
"There is a load of ligament damage. The whole inside of my ankle pretty much took a good old tear.
"Everything else has healed as normal, but there is some tendon damage as well. They are causing the issue and take longer."
He confirmed that the ankle has not bothered him while riding his MotoGP bike.
"No. No issues at all," he said.
Smith is currently one place and six points behind top satellite rider Cal Crutchlow (LCR Honda) in the championship standings, heading into this weekend's event at Jerez.