Michael Joseph Porcaro was an American bass player known for his work with Toto. He retired from touring in 2007 as a result of being diagnosed with amyotrophic lateral sclerosis (ALS) and passed away in March of 2015. He was the middle brother of Toto members Jeff Porcaro and Steve Porcaro. Their father is jazz drummer-percussionist Joe Porcaro. Mike worked as a session bass player before replacing Toto original bass player David Hungate in 1982 shortly after the band completed recording the Toto IV album.