De Los Santos, 26, split the majority of last season between Triple-A Sacramento in the Oakland Athletics organization and Triple-A Nashville in the Brewers organization, combining to go 2-3 with a 5.80 ERA (32 ER/49.2 IP) and 60 strikeouts against 20 walks in 39 relief appearances. The right-hander was acquired by the Brewers on July 29 this past season in exchange for catcher George Kottaras. After being acquired by Milwaukee he went 1-0 with a 1.98 ERA (3 ER/13.2 IP) and 17 strikeouts against just four walks in 11 outings for Nashville.
Originally signed by the Chicago White Sox as a non-drafted free agent in December of 2005, De Los Santos has gone 3-2 with a 4.21 ERA (17 ER/36.1 IP) and 46 strikeouts against 20 walks in 40 relief outings over parts of two Major League seasons (2011-12), both with Oakland. Across parts of seven minor league seasons in the White Sox (2006-07), Athletics (2008-12) and Brewers (2012) organizations, he has gone 19-19 with a 3.59 ERA (132 ER/331.1 IP) and 425 strikeouts against 123 walks in 147 games, 41 starts.
Valdez, 23, spent the entire 2012 campaign with Double-A San Antonio, hitting .225 (104-for-462) in 128 games for the Missions. The infielder was originally signed by the Padres as a non-drafted free agent in November of 2005. Over parts of seven minor league seasons (2006-12), all with the Padres organization, he has hit .252 (584-for-2318) with 133 doubles, 24 triples, 46 home runs, 292 RBI, 354 runs scored and 121 stolen bases in 596 games played.