The 33-year-old Guthrie returned from the injury on Tuesday in San Francisco and held the Giants to one unearned run on four hits in 5 1/3 innings, but left after 90 pitches. The Rockies won, but blew Guthrie's lead, so his effort didn't earn him the victory.
Guthrie said he is recovering well between starts and expects to give the team greater length on Sunday when he faces the Mariners at Coors Field in the finale of the Interleague series.
"I didn't feel any different from any other start. I felt pretty strong, even at the end," Guthrie said. "I felt pretty normal, other than being a little rusty at the start, facing Major League hitters. I wasn't able to get into the strike zone."
For Guthrie, the hardest part of missing time was not the rehab road back, but having to helplessly watch the games.
"It was tough not to be there for the team, especially when we struggled," Guthrie said. "We're trying to get the pitching staff more consistently better. It's good to be a part of it. Hopefully, I can go out there, work deeper into games and have everybody feed off each other."
Guthrie is 2-5 with a 3.72 ERA in nine starts against the Mariners. In his last outing against Seattle, he tossed a complete game, giving up three runs, all unearned, but was issued the loss in eight innings.
For the Mariners, it will be Blake Beavan on the bump. The right-hander will be facing the Rockies for the first time in his career.
Sunday will also be the 23-year-old's first start in a National League park, which means he'll have to make his Major League debut in the batter's box.
"The last time I took live BP was my senior year in high school," Beavan said. "It'll be fun. I'm not going up there expecting much, but if I put the ball in play, I think I'll be happy. Hopefully I'll be bunting every time, because that would mean I'm moving guys over into scoring position."
Mariners: Olivo could return within a week
Miguel Olivo, who has been on the disabled list since May 1 with a strained groin, is on pace to return to the Mariners during the upcoming homestand, perhaps by the end of next week.
"He looks good," manager Eric Wedge said Saturday after watching him work out with the team for two days. "He's strong, he works his tail off. He had another good day today."
Olivo arrived Friday afternoon in Colorado and could head out Sunday to begin a Minor League assignment.
"Tentatively, what we're planning on doing is sending him to Iowa tomorrow," Wedge said. "The [Triple-A] club's heading to Iowa. He'll play for Tacoma there on Monday. We plan on catching him a little bit on Monday, DH on Tuesday, and see where he is from there. We'll probably catch him five innings on Monday and DH him the whole game on Tuesday. He's going to need to catch again at least one more time, but that will depend on how he feels on Monday and Tuesday."
Rockiers: De La Rosa is set back
Jorge De La Rosa's left forearm tightness has led the Rockies to halt his rehab assignment, the team announced Saturday.
De La Rosa was 5-2 with a 3.51 ERA when he underwent Tommy John surgery a year ago. In his first start at Double-A Tulsa on May 12, the tightness limited him to one inning. He threw four innings Thursday and experienced tightness at the end.
"It's very disappointing," said De La Rosa, who would have started at Triple-A Colorado Springs on Tuesday. "I pitched good last time, but I felt a little tightness. They want me to pitch more time in the Minors. I have to do whatever they want.
"I want to be here, but like they say, I need more time. I have to pitch more, build more pitches, to be ready to be here. They want to make sure everything is OK. It hasn't been a year since I had the surgery. They know how hard it is."
• The Rockies became the 27th different Major League team the Mariners have shut out on Friday. The only remaining teams are the Braves (nine games) and the Giants (22 games).
• Friday was the fifth straight game the Rockies starting pitcher has allowed two earned runs or less. That streak ended Saturday with Christian Friedrich surrendering eight earned runs over five innings.