M. Castro makes Rockies' Opening Day bullpen

Hard-throwing right-hander was acquired in Tulowitzki deal

M. Castro makes Rockies' Opening Day bullpen

SCOTTSDALE, Ariz. -- Needing power arms for the bullpen, the Rockies informed right-hander Miguel Castro -- part of last summer's Troy Tulowitzki trade with the Blue Jays -- that he has made the Opening Day roster.

Castro, 21, has thrown consistently in the 95-97 mph range this spring, during which he has eight strikeouts in eight one-inning outings and a 3.38 ERA. The Rockies loaded up on bullpen veterans during the offseason, but they also have spent time seeking young power pitchers. Castro, who spent time in 2015 as the Blue Jays' closer despite being the third-youngest player to make his Major League debut last year, qualifies.

Castro was 0-2 with a 4.38 ERA and four saves in six opportunities for the Blue Jays before being sent to the Minors. After the trade, he went 2-0 with a 1.32 ERA in 11 games at Triple-A Albuquerque. He went 0-1 with a 10.13 ERA in five games with the Rockies before being shut down because of back pain. But he recovered to pitch well in instructional ball, and he has impressed this spring. Castro replaces some of the velocity the Rockies lost when Jairo Diaz suffered a season-ending right elbow injury earlier in camp.

"We collected some power, brought it into camp, and it's maybe one of the differences this year than in the past," Rockies manager Walt Weiss said. "Miguel Castro is a big part of that."

The Rockies are still discussing how many pitchers will be in the bullpen to open the season. Colorado plans to go with a four-man rotation until either April 14 or April 16 due to off-days.

Two spots will go to righty Christian Bergman and lefty Chris Rusin, who will serve as long relievers. It is expected that the Rockies will build Rusin's pitch count to the point that he can take a spot in the rotation. With righty and potential closer Jason Motte expected to begin the season on the 15-day disabled list, the righties are Bergman, Castro, Chad Qualls and Justin Miller. Lefties are Rusin, Boone Logan and Jake McGee.

If it's an eight-man bullpen, the final spot is between righty Scott Oberg, who gave up six hits and seven runs while retiring one batter against the Cubs on Wednesday, and non-roster lefty Jason Gurka, who has 19 strikeouts in 9 2/3 innings and a 1.86 ERA this spring.

Second time's a charm

Gurka, who made his big league debut last year (0-0, 9.39 ERA in nine games) after spending 2008-15 in the Minors, has a chance to make some strides in 2016.

Gurka was hit hard in his late-season debut. But pitching coach Steve Foster saw that Gurka's curveball was much better when he was taller through his delivery. Gurka has corrected the flaw this spring, and he has a chance to grab an Opening Day roster spot. If not, he would be on the short list for a callup if his quality continues.

"I think it's more of getting comfortable, being there, being used to the new teammates and feeling like you belong," Gurka said. "I don't know why I do that, but it always takes me the second time around to have some success. Not to mention I changed my mechanics."

Gurka pitched in the Orioles' system from 2008-14 before finally breaking through with the Rockies. There was some uncertainty when the Rockies took him off the Major League roster after last season, but Gurka is glad he was invited back on a Minor League contract.

"I knew I liked it here, and when they were allowed to talk to me again they gave me a good enough deal, and I felt comfortable coming back to a place where I've already been," Gurka said.

Worth noting

• The Rockies reassigned righty Simon Castro (6 1/3 scoreless innings in nine appearances this spring) to Minor League camp. Castro went 2-0 with a 6.10 ERA in 11 games with the club last season.

• Weiss has not fully announced the rotation, but he said that righty Chad Bettis will start the second game of the regular season -- Tuesday night at Arizona -- after lefty Jorge De La Rosa starts Opening Day. Weiss hasn't determined the order for Wednesday's game and the home opener on Friday. Righties Jordan Lyles and Tyler Chatwood are in play.

• Right-hander Jon Gray, out with an abdominal strain, reported feeling healthy after a 40-pitch bullpen session -- two 20-pitch innings -- Wednesday. Gray said fielding drills and facing hitters are his next steps.

• Bettis pitched Thursday for Albuquerque against the Brewers' Triple-A Nashville affiliate. He gave up two runs, with the only hits being a pair of solo home runs. Bettis struck out one with no walks, and he threw 24 of his 34 pitches for strikes.

Thomas Harding is a reporter for MLB.com. Follow him on Twitter @harding_at_mlb, listen to podcasts and like his Facebook page. This story was not subject to the approval of Major League Baseball or its clubs.