Nicholas Castellanos homered and drove in four runs to propel the Chicago Cubs to a 6-1 interleague sweep of the Seattle Mariners Tuesday night at Wrigley Field. Jon Lester worked out of several jam and went six innings to win his second straight game. The contest also marked the return of Willson Contreras and Ben Zobrist to the Cub lineup. The win enables the Cubs to remain three games behind the Cardinals in the NL Central and 2 1/2 games ahead of Philadelphia for the final NL wild card. The Cubs are idle Wednesday and will open a key NL Central series Thursday in Milwaukee against the Brewers.