Bergman (3-4, 5.29 ERA in nine starts) and Butler (1-1, 5.56 in two starts) each missed significant time with injuries -- Bergman with a broken left hand, Butler with a right rotator cuff strain. With both expected to be in competition for rotation spots in Spring Training 2015, the Fall League will give them an opportunity to acquire timing and consistency, and work on specific assignments.
Bergman, 27, a 2010 24th-round Draft pick out of the University of California, Irvine, suffered his injury when hit with a line drive during his third Major League start, on June 20. Since returning to the Majors Aug. 4, he is 3-2 with a 4.46 ERA in six starts, but has given up fewer than three runs in four of those games. Bergman arrived with a good changeup that offsets his fastball and cutter, but he wants even more diversity.
"I want to make up for the time that I lost and also work on some stuff -- I want to develop my curveball," he said. "It's probably my fourth pitch, but I'd like to bring it up to the level my other offspeed is."
Butler, 23, a supplemental first-round Draft pick out of Radford University in 2012, suffered his injury in his Major League debut, a loss to the Dodgers on June 6. He spent most of the rest of the year rehabbing and helping Double-A Tulsa to the Texas League Championship Series. But Butler returned Saturday and held the D-backs to one run in six innings for his first Major League win.
"I just need to get my arm slot consistent -- that's been the big thing this year," Butler said. "I've found it, but now it's getting it consistent again."
Aquino, 21, went a combined 5-10 with a 5.13 ERA this season in 16 starts at Class A Modesto and two at Tulsa. Aquino dealt with early-season shoulder stiffness.
Roberts, 26, went 9-2 with a 2.30 ERA with 54 strikeouts and 20 walks in 78 1/3 innings at Tulsa this season. The Rockies selected Roberts in the 25th round in 2010 out of Middle Tennessee State.
Rockies Fall League-bound position players are catcher Chris O'Dowd (Tulsa), catcher-first baseman Ryan Casteel (Tulsa), middle infielder Taylor Featherston (Tulsa) and shortstop Trevor Story (Tulsa). Also, Tulsa manager Kevin Riggs will be hitting coach for Salt River.