In 1969 the expansion Pilots traded Lou Piniella
, who won the Rookie of the Year
award that season, to the expansion Royals for Gelnar and outfielder Steve Whitaker
Gelnar compiled a 3-10, 3.31 record starting and relieving. When the team moved to
Milwaukee in 1970, he had his only winning season, going 4-3 with four saves.