 However, the offseason has been most notable for the acquisition of longtime Mariners outfielder Ken Griffey, Jr., nearly 10 years after trading him to the Cincinnati Reds.Other notable acquisitions have included outfielders Franklin Gutiérrez and Endy Chávez (both from the Putz trade), new closer David Aardsma (traded by Boston Red Sox) and long-time Kansas City Royals infielder Mike Sweeney (free agent).This season also marks the 10th anniversary of Safeco Field, the Mariners' home stadium which opened its gates July 15, 1999.