DENVER -- The Colorado Rockies will try to sweep their three-game series with the San Francisco Giants on Sunday after beating them for the fifth time in six games this season with a 12-3 thrashing Saturday night.

Jeff Samardzija will start for the Giants, continuing what for him has been a peculiar schedule this season as he has faced just two teams. His first two starts were against Arizona before he faced the Rockies in San Francisco last weekend.

In a seven-inning outing and 4-3 loss to the Rockies last Sunday, Samardzija surrendered four hits and three runs to the first four batters he faced and then settled down to allow four hits and one run the rest of his outing.

He is 0-3 with a 6.16 ERA in his three starts this year but with six walks and 24 strikeouts in 19 innings. Against the Rockies, Samardzija is 3-3 with a 2.55 ERA in 12 career games, including eight starts. He has been even better at Coors Field, going 2-0 with a 2.15 ERA in six games, including three starts.

"I think the pitches I throw play well here, the sinkers and cutters," Samardzija said. "I'm not a big curveball guy or up and down in the zone type guy."

Samardzija can run his fastball into the mid-90s and his cutter in the 92-93 range, which he said, "is big against a team like Colorado that has a lot of power and can smell those fences here in this park. You got to keep guys off balance, in and out and just stay off the barrel."

Then there's the heightened awareness that comes from pitching at Coors Field, where fly balls go farther in the mile-high altitude.

"The other thing, too, is coming in here you know you have to be on point and locate your pitches," Samardzija said. "That might have something to do with it, too, just understanding that the margin for error is smaller here."

Rookie left-hander Kyle Freeland will start for the Rockies. The Denver native made his major-league debut in the team's home opener April 7 and held the Dodgers to four hits and one run in six innings and won 2-1 in a dazzling performance.

The going has subsequently been harder for Freeland, who is 1-1 with a 4.91 ERA in three starts and will face the Giants for the first time.

In his last start Tuesday at Dodger Stadium, Freeland was unable to qualify for the victory. He was lifted after walking and hitting the two batters he faced in the fifth with a 4-1 lead in a game the Rockies won 4-3. He only allowed four hits but had 10 baserunners, as he walked four and hit two batters while striking out three and throwing 87 pitches, including 45 strikes.

"In that last start, I think I was trying to put every single pitch into a soup can," Freeland said, "and just like hit a spot perfectly. That kind of worked against me at times, because (there were) a lot of deep counts, a lot of long at-bats, four walks."

Freeland said he needs to get back "to filling up the zone and attacking hitters."

To that end, Rockies manager Bud Black said Freeland has been working on a minor mechanical adjustment with his stride direction and his line to the plate to get better fastball command.

"His fastball has got good movement," Black said. "He's got to get to the point where the arm-side fastball, down and away to the righty and in to the lefty, has to become sort of a consistent benchmark for him. Through the early stages here, he's been trying to make that a part of his game plan going in, and it's just been a little variable.

"Part of what makes him good is his angles to the hitter are just a little funky, and it's OK. But we got to just straighten that stride a touch, and he's got to remember to hit the release point out front consistently."