SEATTLE -- Outfielder Jarrod Dyson is day to day after tweaking his right groin in Saturday's 7-6 walk-off win over the A's, Mariners manager Scott Servais said Sunday.
"He felt it a little bit last night, didn't feel that he was running at 100 percent," Servais said. "I think he felt it coming out of the box on the ground ball he hit. I think he thought it was best to pull out of the game at that point."
Guillermo Heredia entered the game in center field for Dyson in the sixth inning.
Dyson was on the disabled list Aug. 19-31 with a right groin strain.
The left-handed Dyson was not available Sunday and won't play Monday, when the Mariners face Houston left-hander Dallas Keuchel. The hope is he'll be ready to face Justin Verlander, who will make his debut with the Astros on Tuesday.
"Hopefully [Dyson] feels OK from there," Servais said. 
Mariners might shuffle rotation
Servais said that the Mariners will assess the rotation after Yovani Gallardo stumbled out of the gates and Marco Gonzales excelled in four innings of relief Saturday.

"We'll talk about where we're at going forward," Servais said. "I thought Marco Gonzales really saved our bacon last night, he threw great. Did some things that he hadn't been able to do, as far as getting the ball consistently to the glove side on the righties, which opened up his changeup. He did a lot of things, great pickoff move, which was a big out in that game. It was really nice to see a positive outing."
Servais said he was encouraged by Gonzales, who was removed from the rotation following the Mariners' acquisition of Mike Leake from the Cardinals, as a prime candidate to claim Gallardo's turn if the Mariners remove him from the rotation. Gallardo's next start, based on the current rotation, would be Friday against the Angels.

"I thought after [his] first inning [Gonzales] threw the ball better every inning after. I think he got in a better rhythm," Servais said. "He threw all of his pitches out of the stretch last night, I think he has a little bit of a windup anyway, but out of the stretch his direction is better, his arm gets on top a little quicker, a lot of good things there.
"As far as the rotation goes, we'll talk about it, see what fits best. But I like what Marco did last night."