Seattle made the moves before Monday's series opener against the New York Yankees.
Taylor made 18 starts and appeared in 20 games since being called up on May 6 but was slumping at the plate. Taylor was hitting .159 with just one RBI and 19 strikeouts. Taylor was hitless in his final 12 at-bats before being sent down.
Guaipe appeared in 16 games at Tacoma and had 18 strikeouts and three walks in 19 2/3 innings.
Seattle manager Lloyd McClendon announced left-hander Mike Montgomery would start Tuesday against the Yankees, with James Paxton on the 15-day disabled list. A move to clear a roster spot for Montgomery will be made before Tuesday's game.