DENVER -- Quite literally, the difference in performance for Colorado Rockies left-hander Kyle Freeland has been night and day.

Not that Freeland (9-7, 3.67 ERA), who will start the rubber game of the series on Sunday against the Pittsburgh Pirates and Ivan Nova (10-6, 3.27), has any explanation for his astounding success in day games versus those played at night.

Freeland is 7-2 with a 2.89 ERA in 10 day starts and 2-5 with a 4.69 ERA in nine games (eight starts) at night.

Freeland, who was born and raised in Denver, made his major league debut on April 7 at Coors Field in the Rockies' home opener against the Los Angeles Dodgers and gave up four hits and one run in six innings and won 2-1.

In Freeland's last start on July 9, he held the Chicago White Sox hitless for 8 1/3 innings before giving up a single and departing after 126 pitches in Colorado's 10-0 romp.

With 107 1/3 innings at that point in Freeland's rookie season, the Rockies took him out of the rotation temporarily. He pitched three hitless innings in his first professional relief appearance on July 15 at the New York Mets and now will return to the rotation, replacing injured Tyler Chatwood and taking the Coors Field mound, yes, in the day.

"I don't read too much into it," Freeland said of the disparity between his performance in day and night games. "Obviously, my record for day games versus night games is better, but for me, it's just how things have played out this season. Next season, it could be flipped. I could have better outings at night than (in the) day.

"I have no thought process on that. It's just another baseball game, day or night. I'm going to attack it the same."

Freeland is 0-1 with a 6.35 ERA against the Pirates. In his one career start against them on June 12 at Pittsburgh, he allowed nine hits and five runs (four earned) in 5 2/3 innings and lost 7-2.

Nova won his last start on Tuesday against Milwaukee, allowing 10 hits and three runs in six innings with one walk and six strikeouts in the Pirates' 4-3 victory. He has won back-to-back starts and five of his past seven decisions. Nova has pitched at least six innings in 18 of 19 starts.

Nova is 0-2 with an 8.40 ERA in three career starts against the Rockies, all coming with the New York Yankees -- the last on June 21, 2016, at Yankee Stadium. He's 0-1 with a 9.00 ERA in one start at Coors Field, where he allowed five runs and 10 hits in five innings on June 15, 2016.

Pirates rookie first baseman Josh Bell is thriving during the current series with the Rockies. He had his first career four-hit game in Pittsburgh's 13-5 win on Friday, going 4-for-6 with four RBIs. Bell hit his 18th homer Saturday when the Pirates lost 7-3.

Bell's 18 homers are tied with Al Martin (1993) for the fifth most by a Pirates rookie in franchise history and the most by a rookie since Garrett Jones hit 21 in 2009. Bell has hit safely in 12 of his past 14 games, going 20-for-57 (.351) during that span.

"He can fire early (in the count) and hurt you," Pirates manager Clint Hurdle said. "He can see pitches, foul off pitches. He can take a funny swing and then barrel a ball up and hit it 110 miles an hour. He's been fun to watch develop, and he's still figuring things out.

"The way I gauge players, there's guys I don't want to miss when it's their turn at-bat. (Barry) Bonds was in that category. The guy over there that plays third base (Nolan Arenado), I would not go to the bathroom when his at-bat comes up. And Bell's a guy since he's come up, you know what, we're going to hold off on the popcorn. Go get something to eat after he's done. (You) just don't know what you're going to see."