The Chicago Cubs' search for relief pitching didn't leave the city limits.
Cotts made a career-high 70 appearances for the White Sox last season, going 1-2 with a 5.17 earned-run average. He was 4-0 with a 1.94 ERA in 2005 and earned a win in the White Sox's four-game sweep of the Houston Astros.
In four major-league seasons, all with the White Sox, Cotts is 10-7 with a 4.52 ERA and one save in 199 appearances. In 193 innings he has allowed 178 hits and 106 runs (97 earned) while striking out 169 and walking 100.
Aardsma was 3-0 with a 4.08 ERA in 45 appearances for the Cubs last season, while Vazquez has spent his entire career in the Cubs' minor-league system.
Aardsma made 45 appearances with the Cubs in 2006, going 3-0 with a 4.08 ERA. In two seasons with the Giants and Cubs he's 4-0 with a 4.52 ERA in 56 games.
It's the first trade between the Cubs and White Sox since the White Sox sent Matt Karchner to Wrigley Field in exchange for Jon Garland on July 29, 1998.