The best rookie pitcher in baseball this year is back on the mound.

Kyle Freeland will start for the Colorado Rockies on Tuesday, facing the Atlanta Braves in game two of a four-game series at Coors Field. The Rockies optioned Zac Rosscup to Triple-A Albuquerque to make room for Freeland on the roster.

Freeland was placed on the 10-day disabled list on Aug. 5 with a left groin strain. He suffered the groin strain after 0.1 innings pitched in his last start, Aug. 4, a 4-3 victory over the Phillies.

He is 11-7 with a 3.70 ERA (121.2 IP, 50 ER), 44 walks and 77 strikeouts across 21 starts and one relief appearance. Among Major League rookie pitchers, Freeland ranks first in wins (11) and ERA among qualifiers (3.70).

Rosscup has made three appearances with the Rockies this season, allowing four runs in 3.1 innings pitched (10.80 ERA) with seven hits, no walks and five strikeouts. He was acquired via trade from the Chicago Cubs on June 26 in exchange for right-handed pitcher Matt Carasiti.

Colorado defeated Atlanta, 3-0, in the first game of the series on Monday spurred by an inspiring performance by starter Chad Bettis. The right-hander made his first MLB start since Sept. 30 after successfully undergoing treatment twice for cancer. Bettis pitched seven scoreless innings, allowing just six hits but earning a no-decision.

First pitch is 6:40 p.m. on Tuesday at Coors Field. Freeland is scheduled to face Sean Newcomb (1-7, 4.45).