Vlasic because he wanted to find a young quarterback to observe and succeed Dan Fouts. He signed with the team in late July, and spent the preseason competing with Rick Neuheisel, Tom Flick, and others for the backup quarterback job. While he performed well in the preseason, the Chargers were looking to have him sit out a year so he could learn the ins-and-outs or pro football. After Flick was cut and Mark Herrmann named the primary backup, Vlasic beat out Neuheisel for the final quarterback spot on the Chargers' roster, though Neuheisel would rejoin the team later that season due to the strike. Despite making the roster, Vlasic spent most of the season after the players' strike on the team's inactive list. However, when Fouts was scratched from a December game against the Denver Broncos due to a shoulder injury, Vlasic was called up to be Herrman's backup. He made his professional debut on December 27, 1987, playing the final 5:29 of the game. He completed three of six passes for eight yards, was sacked, and threw an interception in the Chargers' 24-0 loss against Denver.