Castro tossed a scoreless inning in Wednesday's 3-1 loss to the Diamondbacks.

Castro has appeared in 10 games in relief for the Rockies since his contract was purchased from Triple-A Albuquerque in late August. During that time, he's compiled a 4.66 ERA, 1.44 WHIP, and 9:4 K:BB ratio over 9.2 innings, numbers that haven't made a compelling case for high-leverage duty. He doesn't project to be a key member of the Rockies' bullpen in 2016.

Castro's contract was purchased from Triple-A Albuquerque prior to Sunday's game against the Mets, MLB.com's Thomas Harding reports.

Castro will join the Colorado bullpen to replace Rafael Betancourt, who was designated for assignment Sunday in a corresponding move. The 27-year-old, who last appeared in the majors in 2013 with the White Sox, has posted a 3.79 ERA and has struck out 74 batters across 57 innings this season at Albuquerque.

Rockies signed RHP Simon Castro to a minor league contract.

Castro made it up to the majors briefly with the White Sox last season but spent most of the year at Triple-A, posting a 5.83 ERA and 1.41 WHIP. He's merely organizational depth.

White Sox sent RHP Simon Castro outright to Triple-A Charlotte.

Castro allowed two runs over 6 2/3 relief frames during his time with the White Sox this season. The 25-year-old will surely get invited to big league camp in spring training.

White Sox recalled RHP Simon Castro from Triple-A Charlotte.

Castro will replace Brian Omogrosso on the active roster. The 25-year-old right-hander has 4.92 ERA over 16 appearances (12 starts) at the Triple-A level this season and will serve in a long relief role.

White Sox acquired RHP Simon Castro and LHP Pedro Hernandez from the Padres for OF Carlos Quentin.

Padres purchased the contract of RHP Simon Castro from Triple-A Portland.

The team's top pitching prospect, Castro posted a 3.28 ERA, 1.18 WHIP and 113/42 K/BB ratio over 140 innings between Double- and Triple-A this past season. The 22-year-old is expected to get a look in spring training but is likely to begin 2011 back at Triple-A.

The San Diego Union-Tribune expects top prospect RHP Simon Castro to get a "long look" in spring training but to ultimately begin the season at Triple-A.

The 22-year-old posted a 3.28 ERA, 1.18 WHIP and 113/42 K/BB ratio over 140 innings between Double- and Triple-A this past season (just two starts coming at Triple-A). Armed with a fastball that touches the mid-90s and a plus slider, Castro has significant upside, especially with PETCO as his home park. The Dominican native will be someone to keep an eye on this spring.

Padres prospect right-hander Simon Castro tossed five shutout innings for Double-A San Antonio on Friday night.

Castro, who turned 22 on Friday, was making his Double-A debut. Armed with his plus-fastball, he struck out five and walked two in the effort. The 6-foot-5 right-hander emerged as the organization's top pitching prospect last season with Class A Fort Wayne, going 10-6 with a 3.33 ERA, 1.11 WHIP and 157/37 K/BB ratio in 140 1/3 innings.