Clarke said he has been practicing the drill for several years now, on the suggestion of fielding coach Mike Young, who was a former baseball coach.
"Youngy introduced me to it, it just makes you watch the ball a little bit closer and it is a good drill," Clarke was quoted as saying by the Herald Sun.
Spin coach John Davison was the pitcher as Clarke slogged the throws all over the ground. One of the shots also hit former Test cricketer Greg Chappell on his chest.
Asked about his fitness, the 33-year-old said, "I am sick of saying it but it really is one day at a time. I feel like I'm improving slowly every single day. The medical staff dictate how hard I can push but everyone is really happy at the moment."