Cosart, 26, has gone 3-5 with a 4.14 ERA (27 ER, 58.2 IP) and 34 strikeouts against 26 walks in 12 minor league starts this season, including 10 for Triple-A New Orleans, while also making four starts for Miami including his last outing. Originally signed by the Philadelphia Phillies as a 38th-round selection in the 2008 First-Year Player Draft, the right-hander was acquired by the Astros in a four-player trade with the Phillies in July 2011 for outfielder Hunter Pence before being acquired by the Marlins in July 2014 from the Astros in a six-player trade. Over parts of four Major League seasons with the Astros (2013-14) and Marlins (2014-16) he has gone 16-18 with a 3.69 ERA (135 ER, 329.2 IP) and 206 strikeouts against 157 walks in 58 games, 57 starts.
Capps, 25, is currently on the 60-day disabled list after undergoing season-ending Tommy John surgery on his right elbow earlier this year in March. In 2015 for Miami he went 1-0 with a 1.16 ERA (4 ER, 31.0 IP) and 58 strikeouts against seven walks and a .168 (18-for-107) opponents batting average in 30 relief appearances for Miami. The right-hander was originally signed by the Seattle Mariners as a third-round selection in the 2011 First-Year Player Draft out of Mount Olive College (NC) and acquired by Miami in December 2013 in exchange for infielder Logan Morrison. Over parts of four Major League seasons with Seattle (2012-13) and Miami (2014-15), he has gone 4-3 with a 3.99 ERA (60 ER, 135.1 IP) and 177 strikeouts against 46 walks in 118 relief appearances.
Castillo, 23, has gone 7-3 with a 2.25 ERA (25 ER, 100.0 IP) and 84 strikeouts against just 15 walks while holding opponents to a .223 average in 20 games, 18 starts, for Single-A Jupiter this season, being named a 2016 Florida State League Mid-Season All-Star this year. The right-hander came into this season ranked by MLB.com as the Marlins No. 6 prospect. A native of the Dominican Republic, he was originally signed by the San Francisco Giants in December 2011 before being acquired by Miami as part of a three-player trade in December 2014. Over parts of five minor league seasons in the Giants (2012-14) and Marlins (2015-16) organizations he has gone 16-15 with a 2.71 ERA (105 ER, 348.1 IP) and 325 strikeouts against 98 walks over 149 games, 34 starts.
Cashner, 29, has gone 4-7 with a 4.76 ERA (42 ER, 79.1 IP) and 67 strikeouts against 30 walks in 16 starts for San Diego this season. The right-hander was acquired by the Padres in January 2012 as part of a four-player trade with the Chicago Cubs. Originally signed by the Cubs as a first-round selection (19th overall) in the 2008 First-Year Player Draft out of Texas Christian University (TX), he has gone 30-49 with a 3.73 ERA (279 ER, 673.2 IP) and 563 strikeouts against 225 walks over 190 games, 98 starts, in his seven-year Major League career with the Cubs (2010-11) and Padres (2012-16).
Rea, 26, has set career-highs for the Padres this season in nearly every category, going 5-5 with a 4.98 ERA (55 ER, 99.1 IP) and 76 strikeouts against 44 walks with a .262 (101-for-385) opponents batting average in 19 games, 18 starts. The right-hander was signed by the Padres as a 12th-round selection in the 2011 First-Year Player Draft out of Indiana State University (IN). Having made his Major League debut for San Diego last season, he has gone 7-7 with a 4.81 ERA (70 ER, 131.0 IP) and 102 strikeouts against 55 walks in 25 games, 24 starts, over his two Major League campaigns (2015-16) for San Diego.
Guerrero, 25, has gone 0-3 with a 5.30 ERA (21 ER, 35.2 IP) and 36 strikeouts against 19 walks over 32 minor league relief outings this season between Double-A San Antonio and Triple-A El Paso. A native of Colombia, the right-hander originally signed with the Padres as a free agent in May 2010. He made his Major League debut for the Padres earlier this season with one relief appearance. Over parts of seven minor league seasons (2010-16) in the Padres organization he has gone 13-21 with a 4.09 ERA (131 ER, 288.0 IP) and 288 strikeouts against 190 walks in 182 games, 20 starts.