Castro, a hard-throwing non-roster invitee, has made an impression with his aggressiveness and performance over his first two spring appearances, Jane Lee of MLB.com reports. "He's pretty passionate about what he does, and when he came to the mound, he was pretty vocal," A's manager Bob Melvin said. "He was telling the guys, 'Let's go! Right now, let's go!' I haven't heard that too many times out of pitchers, let alone in Spring Training, so he impressed me with his eagerness to pitch and certainly was not scared and got the outs we needed.

EDGE Analysis

The 28-year-old Dominican has been hard to miss when out on the mound, both for his demeanor and ability to successfully navigate difficult situations. Castro has a 1-0 record on the strength of a scoreless inning across two appearances, earning the win by getting two outs after inheriting a man on third in Monday's victory over the Giants. He also limited further damage in the second inning of the Cactus League opener by coming on in relief of Jesse Hahn after the latter had already given up three runs in the frame. The 6-foot-5 Castro has limited big league experience -- having posted a 4.76 ERA and 1.41 WHIP over 17 innings with the White Sox and Rockies in the 2013 and 2015 seasons -- but has built up a solid minor league resume following a transition to reliever after 2014 Tommy John surgery. Castro has compiled an impressive 132 strikeouts over 110.1 innings at Triple-A Albuquerque during the 2015-16 campaigns and is arguably making the biggest impact of the 14 non-roster pitches in Oakland camp this spring.

Castro signed a minor league contract with Oakland on Thursday that includes an invite to spring training, CSN Bay Area reports.

EDGE Analysis

Castro put together a solid showing at Triple-A Albuquerque in 2016, where he was one of the club's most-used relievers, as he threw for a 3.38 ERA and 1.20 WHIP over 53.1 innings (50 games). He also posted a 25.8 percent K-rate, which is well above his career average of 20 percent, and managed to walk batters at a career-low rate of 5.3 percent.

Castro was optioned to Triple-A Albuquerque on Thursday, Nick Groke of The Denver Post reports.

EDGE Analysis

The Rockies trimmed their roster down to exactly 40 men Thursday with the move to option Castro down to Triple-A. Castro struck out four batters while allowing zero runs across 5.1 innings of work this spring. He figures to provide depth out of the bullpen at Albuquerque for most of the season.

Castro signed a minor league contract with the Rockies on Thursday that includes an invitation to spring training.

EDGE Analysis

Castro pitched well with Triple-A Albuquerque last season, but he failed to perform well once he received a promotion to the majors. It will be tough for Castro to crack the Rockies bullpen unless significant improvements are made.

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

EDGE Analysis

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.

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.