Weeks, who turns 29 on Jan. 26, has played parts of five seasons at the big league level with the A's, Orioles and Red Sox. He had three hits in nine at-bats with the Red Sox in 2015, spending most of the season at Triple-A Pawtucket, where he hit .204.
Weeks, the 12th overall pick of the A's in 2008, is a second baseman by trade, but he can move around the diamond. His best season was his rookie year with Oakland in '11, when he hit .303/.340/.421 in 437 plate appearances.
Weeks gives the Padres some organizational depth in the infield, as does Rosales, who signed his Minor League deal with the Spring Training invite on Jan.