DENVER -- The Rockies, who are controlling rookie right-hander Antonio Senzatela's Major League innings, optioned him to Triple-A Albuquerque on Saturday for one start, with plans to return him to the rotation.
The Rockies recalled left-handed reliever Zac Rosscup, acquired in a June 26 trade with the Cubs for righty reliever Matt Carasiti, to fortify the bullpen.
Senzatela (9-3, 5.63 ERA) earned National League Rookie of the Month honors in April and still leads the Rockies -- who will finish the pre-All-Star schedule in position for the second NL Wild Card -- in wins. But his history and recent performance trends led the Rockies to pull him from the rotation. After going 2-3 with an 8.54 ERA from May 21-June 22, his last three outings have been in relief.
Senzatela, 22, said he will start July 13 in Las Vegas, in Albuquerque's first game out of the Pacific Coast League All-Star break. 
"They told me I'd throw on [July 13] and come back here and start on the 18th; that's the plan," Senzatela said. "I need to keep the ball down, the way I was doing the first two months, and make more quality pitches."
Senzatela threw just 34 2/3 innings for Double-A Hartford last season because of two bouts with right shoulder inflammation and the illness and death of his mother in Venezuela. Injuries and a strong Spring Training netted him a Major League rotation spot.
Rockies manager Bud Black said Senzatela's velocity was down "a tick" -- his fastball went from 94.3 mph in May to 94.0 in June, according to Statcast™ -- in his last two starts before going to the bullpen. In three relief outings covering five innings, the four-seamer has climbed to a 95.3 mph average.
"He's been going hard since early February, as with all our young pitchers," Black said. "These guys were really grinding to try to make the team and haven't stopped."
Black acknowledged that lefty Kyle Freeland, who will start against the White Sox in Sunday's final game before the break, could be a candidate for an innings slow-down coming out of the break. Righty German Marquez's solid performance in Friday's 12-4 victory over the White Sox -- seven innings, three earned runs, five strikeouts -- occurred with enough time left before the break that the Rockies can build in extra rest before his next start.
Worth noting
• Rosscup will give the bullpen four lefties and four righties. Rosscup's lone Major League appearance this year was on May 22 -- a scoreless two-thirds of an inning against the Giants. He missed all of 2016 with left shoulder inflammation. Before the injury, he spent parts of three seasons with the Cubs, appearing in 61 games from 2013-15 with a 5.40 ERA.
In Triple-A with the Cubs and Rockies affiliates, Rosscup had a combined 2.53 ERA in 31 1/3 innings over 20 appearances, including one start.
Major League righties are hitting more than 100 points higher against Rosscup than lefties -- .287 compared to .162. At Triple-A, he has been fed a steady diet of righties.
"It's definitely something I could work on, I haven't had that much success against righties in the big leagues," Rosscup said. "But now I have more of a plan of attack. I don't think there's anything different that I'm doing, it's more about having a plan."