Claim: Mike Portnoy was replaced by Mike Mangini in Dream Theater.

Michael Stephen `` Mike '' Portnoy -LRB- born April 20 , 1967 -RRB- is an American drummer primarily known as the former drummer , backing vocalist , and a co-founder of the progressive metal/rock band Dream Theater . Known for his technical skill as a drummer , Portnoy has won 30 awards from the Modern Drummer magazine . He co-produced six Dream Theater albums with guitarist John Petrucci , starting from Metropolis Pt . 2 : Scenes from a Memory through Black Clouds and Silver Linings . From A Change of Seasons onwards , Portnoy had been writing a significant amount of Dream Theater 's lyrics . He is the second youngest person -LRB- after Neil Peart -RRB- to be inducted into the Modern Drummer 's Hall of Fame , at 37 years of age .   Besides his work with Dream Theater , Portnoy is known for his many side projects and tribute bands . He is a founding member of Liquid Tension Experiment , an instrumental progressive rock band featuring fellow Dream Theater members John Petrucci and Jordan Rudess along with bassist Tony Levin . He is also a founding member of Transatlantic , a progressive rock `` super-group '' featuring former Spock 's Beard keyboardist/vocalist Neal Morse , Flower Kings guitarist Roine Stolt and Marillion bassist Pete Trewavas . Portnoy has also recorded and/or toured/performed live with Neal Morse , OSI , Hail ! , Stone Sour , Fates Warning , Overkill , G3 and played on Avenged Sevenfold 's album Nightmare in place of their late drummer , The Rev. Over the years , Portnoy has also created tribute bands to The Beatles , Led Zeppelin , Rush , and The Who , which has allowed him to perform the music of his four favorite drummers .   In September 2010 , Portnoy announced his departure from Dream Theater after 25 years . He was replaced by Mike Mangini . Since leaving Dream Theater , Portnoy has formed several new bands . The first , Adrenaline Mob , a traditional heavy metal/hard rock band with singer Russell Allen -LRB- of Symphony X -RRB- and guitarist Mike Orlando . On June 4 , 2013 , however , Portnoy announced his departure from Adrenaline Mob , citing scheduling conflicts . He is also a founding member of Flying Colors , a progressive pop band also featuring Steve Morse , Neal Morse , Dave LaRue , and Casey McPherson ; and The Winery Dogs , a power trio also featuring bassist Billy Sheehan -LRB- Mr. Big -RRB- and guitarist Richie Kotzen -LRB- formerly of Mr. Big and Poison -RRB- .