Putnam again tore up the PCL with Tucson in 1978, batting .309 with 21 home runs and 96 RBIs. He had only two RBIs with the Rangers that season; however, they were both significant. He managed to drive in the only run in their 1-0 victory over the Seattle Mariners on September 22,[2] and two days later, in the Rangers' 5-3 victory at Arlington Stadium over the Mariners, Putnam hit his first major league home run.
Putnam mostly appeared in the line-up as a designated hitter until May 28, 1979, when regular Rangers first basemanMike Jorgensen was hit in the head by a pitch from Boston Red SoxpitcherAndy Hassler.[3] Putnam took over as the Rangers' regular first baseman for the next month. Putnam made the most of the opportunity and batted .277 with 18 home runs and 64 RBIs to finish fourth in Rookie of the Year balloting.
Putnam failed to live up to his early promise, and in 1982 found himself back in the minors with the Denver Bears of the American Association. During the off-season, he was traded to the Seattle Mariners for Ron Musselman.
Final seasons
After a season and a half in Seattle, Putnam was traded to the Minnesota Twins on August 29, 1984. He signed a minor league contract with the Kansas City Royals in 1985, and spent the entire season with their triple A affiliate, the Omaha Royals. He played two seasons in Japan for the Nippon-Ham Fighters in 1986 and 1987 before retiring.