29-year-old american - the most decorated olympian in history with 22 medals , 18 of them golds - will compete at the arena pro swim series event in mesa , arizona , from april 15-18 .
phelps was suspended by usa swimming following his drink-driving arrest in september when police caught him travelling at 84mph in a 45mph zone in baltimore , maryland .
michael phelps has won 22 olympic medals , 18 golds , but was banned from swimming in september .