Staggs made his Major League Baseball debut on July 1, 1977, going 2 for 5 in an 11-8 loss to the Texas Rangers. Staggs first career hit was a home run off of Rangers pitcher Doyle Alexander. Staggs finished the season appearing in 72 games with Toronto, batting .259 with 2 HR and 28 RBI.
Staggs opened the first four games of the 1978 season as Oakland Athletics' starting second baseman, but thereafter was essentially a back-up infielder mostly used as a late inning defensive replacement, although with the occasional spot start. In limited action, Staggs hit .244 with 0 HR and 0 RBI in 47 games with the Athletics. He was sent down to the minors by the end of June.