Maybin, 28, returns to the organization that drafted him. The Tigers took Maybin in the first round in 2005, and he made his major league debut for Detroit in 2007 before being traded to the Marlins as a key prospect in the deal that brought Miguel Cabrera to the Tigers.
Maybin hit .267 with 10 homers, 59 RBIs and 23 steals for the Braves this year.
Krol made 33 relief appearances for the Tigers in 2015, going 2-3 with a 5.79 ERA. Speier pitched in 33 games this year for Class A West Michigan, going 4-2 with a 2.86 ERA.