 On October 8, 1992, Guidinger signed as a free agent with the Cleveland Cavaliers as an undrafted rookie despite having reconstructive surgery on both of his knees prior to his initial tryout with the team.He played for the Cavaliers for two seasons as part of the team's seldom-used backup frontcourt to Brad Daugherty, Larry Nance and John "Hot Rod" Williams, although he was in the starting lineup for five games during the 1992–93 season.He was then waived by the Cavaliers on December 23, 1993, but re-signed with the team for two 10-day contracts on January 19, 1994 before being signed for the rest of the season, his last as a professional.