The deal was announced Saturday.
The 23-year-old Maybin hit .234 with eight home runs and 28 RBIs. He made 74 starts in center field.
Maybin was the 10th overall pick in the 2005 draft and later traded by Detroit in a multiplayer deal for Miguel Cabrera. Once considered one of baseball's top prospects, he's struggled to make consistent contact at the plate in the majors, leading to several trips back to the minors.
The 26-year-old Mujica was 2-1 with a 3.62 ERA in 59 games for the Padres. He struck out 72 and walked just six.
The 24-year-old Webb was 3-1 with a 2.90 ERA in 54 games.