At the age of 20, he joined David Lee Roth's band to work on Roth's album A Little Ain't Enough, replacing Steve Vai, who had joined Whitesnake. In 1990 Becker won the coveted Best New Guitarist award from Guitar Magazine. While preparing for the album, Becker began to feel what he called a "lazy limp" in his left leg. He was soon diagnosed with amyotrophic lateral sclerosis (ALS; Lou Gehrig's Disease) and was given three to five years to live. He finished the recording using lighter (thinner) gauge guitar strings and other techniques, which made it easier for him to play with his weakening hands. Although he managed to finish the album, which was released in 1991, he did not join the supporting tour due to his inability to perform on stage; former Lizzy Borden guitarist Joe Holmes took Becker's place on tour.
His ALS gradually robbed him of his ability to play guitar, to walk, and eventually his ability to speak. He now communicates with his eyes via a system developed by his father. He remains mentally sharp and, with the aid of a computer, continues composing. In the back of the Perspective CD case, Becker states "I have Amyotrophic Lateral Sclerosis. It has crippled my body and speech, but not my mind." His medical condition has remained stable since 1997. In 2003, Becker posted on his website that he was feeling better and had gained some weight, while the folder for his 2008 album Collection also mentions an upcoming book.