Freeland (4-5,3.28 ERA) will oppose veteran right-hander Jeff Samardzija, 33, who is 1-3 with a 6.23 ERA.
Freeland took a three-start winning streak into his last outing on Wednesday and pitched well but lost 3-0 at Los Angeles. He allowed three runs in 6 1/3 innings.
In his past six starts, Freeland has pitched seven innings in three of those and no fewer than 6 1/3 innings in the six games.
During that stretch, Freeland is 4-2 with a 2.01 ERA in 40 1/3 innings, allowing 28 hits, including one homer, and 12 walks with 35 strikeouts. Freeland yielded five homers in his first four starts covering 20 innings and was 0-3 with a 5.85 ERA.
"I think what we saw was improved fastball command, especially inside to right-handed hitters," Rockies manager Bud Black said when asked about Freeland's successful six-start stretch. "I think his slider has had better spin to it, so the rotation on his breaking ball is much more consistent. So that's led to better quality pitches.
"I think the changeup has become a little bit more functional, maybe not in drastic amounts, but in small doses the changeup has been usable. I think those three things just on the fundamental side have been key.
"I think his delivery, he's much more comfortable now at the end of May (with) the delivery he sort of had to work through in spring training and part of April. So I think there's just a total confidence in so many things sort of adding up that it led to this six-start run."
Freeland lives in Scottsdale, Ariz., where the Rockies' spring training complex is located. He began working there on his delivery after Thanksgiving with Darryl Scott, one of the Rockies' pitching coordinators.
Freeland used to have a Clayton Kershaw-like pause and kick with his front leg that led Freeland to being overly rotational in his delivery and not as ideally aligned toward home plate when releasing the ball.
"We found out that by doing that pause at the bottom, it kind of de-loaded me and kind of robbed me of some of my power," Freeland said. "Now I'm holding my weight load up higher and then driving directly down the mound and toward the plate. I'm controlling the zone better and throwing more strikes."
Freeland has thrown a team-leading 60 1/3 innings, which includes three starts at Coors Field, where he's 2-1 with a 1.40 ERA. He's 3-2 with a 2.79 ERA in five starts against the Giants, including one this season at San Francisco on May 17 where Freeland gave up five hits and one run in 6 2/3 innings and won 6-1.
Samardzija has pitched six innings in one of seven starts this season, and the Giants are 2-5 in those games. He gave up four hits, five walks and four runs in 4 2/3 innings while losing 4-1 on Wednesday at Houston.
Samardzija received a no-decision on May 17 against the Rockies in San Francisco, giving up five hits and three runs in 6 2/3 innings in the Giants' 5-3 loss. He's 4-5 with a 3.84 ERA in 16 games (12 starts) against the Rockies and 2-2 with a 4.87 ERA in eight games (five starts) at Coors Field.
After the Giants lost 6-5 in 10 innings Monday, manager Bruce Bochy said ace left-hander Madison Bumgarner, who suffered a broken left hand in spring training, would make a second rehab start Thursday at high-Class A San Jose. He threw 47 pitches in 3 2/3 scoreless innings in his first rehab start Saturday for Triple-A Sacramento.
"Right now, I'm saying, right now, he's scheduled to pitch in San Jose," Bochy said. "Just put him in a situation where we can get him stretched out. He's had one start down there. We'll talk about it some more."
Asked if he might change his mind, depending how the starters fare and the bullpen is used the next two days, Bochy said, "That's always a possibility."