Brentz, who was the Mariners' No. 26-ranked prospect by MLBPipeline.com, spent most of the season with Class A Everett and Clinton, though he did fill in for two games with Triple-A Tacoma as well. The 21-year-old allowed four runs (three earned) in 1 2/3 innings in his two relief appearances for Tacoma, but closed out the year going 3-1 with a 4.35 ERA with 14 strikeouts and six walks in 10 1/3 innings in eight games with Clinton. He was 1-1 with a 5.08 ERA in 10 games for short-season Everett, including seven starts.
Brentz was acquired by Seattle along with left-handed pitchers Rob Rasmussen and Nick Wells from Toronto in exchange for right-handed pitcher Mark Lowe on July 31, 2015. He was an 11th-round Draft pick of the Blue Jays in 2013.
Vasquez, 20, split his season between the Arizona Rookie League Mariners and Clinton, posting a combined mark of 5-4 with a 2.26 ERA with 52 strikeouts and nine walks in 71 2/3 innings in 13 games, including 12 starts. Vasquez, who signed with Seattle out of the Dominican Republic last year, was 3-2 with a 2.28 ERA in eight starts with Clinton.
Caminero, a hard-throwing right-hander, has helped solidify the back end of the Mariners' bullpen and is 1-1 with a 3.86 ERA in 14 innings over 13 appearances. The 29-year-old isn't arbitration eligible until 2018 and is under team control through 2020.
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.