Landa, 21, split the 2015 season between Rookie GCL Twins and Single-A Cedar Rapids, going 3-1, 1.25 ERA (36.0 IP, 5 ER) with one save, 16 walks and 40 strikeouts in 22 relief appearances. The 6-foot-0 right-hander was originally signed as an undrafted free agent out of Venezuela in 2010.
Dean, 26, spent the entire 2015 season with Triple-A Rochester, going 12-11, 2.82 ERA (179.0 IP, 56 ER) with five complete games, three shutouts, 36 walks and 98 strikeouts in 27 starts. His 179.0 innings pitched led the International League last season. The 6-foot-1 left-hander was originally drafted by the Twins in the third round of the 2010 First-Year Player Draft out of Boston College.
Melotakis, 24, missed the entire 2015 season recovering from "Tommy John" surgery, an injury he suffered in 2014. The 6-foot-2 left-hander was originally drafted in the second round of the 2012 First-Year Player Draft. In four seasons in the minor leagues he has posted a record of 19-7, 3.00 ERA (198.0 IP, 66 ER) with 72 walks and 180 strikeouts in 82 appearances (20 starts).
Rogers, 24, spent the 2015 season in the Triple-A Rochester starting rotation, going 11-12, 3.98 ERA (174.0 IP, 77 ER) with two complete games, 44 walks and 126 strikeouts in 28 appearances (27 starts). The 6-foot-3 left-hander was originally drafted by the Twins in the 11th round of the 2012 First-Year Player Draft out of the University of Kentucky.
Rosario, 21, split the season between Rookie GCL Twins and Single-A Cedar Rapids going 3-6, 3.06 ERA (61.2 IP, 21 ER) with 20 walks and 54 strikeouts in 13 appearances (12 starts). The 6-foot-1 left-hander was originally signed by the Twins as an undrafted free agent in 2010 out of the Dominican Republic.
Walker, 24, spent the entire season with Double-A Chattanooga hitting .239 (120-for-502) with 31 doubles, three triples, 31 home runs, 65 extra-base hits and 106 RBI, he led the Southern League in home runs, extra-base hits and RBI. The 6-foot-4 outfielder also played for Scottsdale in the Arizona Fall League, hitting .254 (18-for-71) with two doubles, a triple, five home runs and 18 RBI in 19 games.
Additionally, right-handed pitcher A.J. Achter was claimed off outright waivers by Philadelphia and catcher Josmil Pinto was claimed off outright waivers by San Diego.
The Twins now have 38 players on their major league roster.