MESA, Ariz. -- Renato Nunez, who is already facing an uphill battle in A's camp this spring, will be slowed by a left hamstring injury.
Nunez pulled his hamstring while trying to score in the fourth inning of the A's 8-3 exhibition win over the Padres on Saturday, putting yet another third baseman on the shelf. Matt Chapman is being held out of games while nursing a sore right hand, and now the A's will wait to learn how long they'll be without Nunez.
Hamstring injuries typically aren't kind, often requiring at least a couple weeks of rest.
"I'm not sure how long that's going to be," A's manager Bob Melvin said, "but sometimes hamstrings take a while unfortunately."
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Nunez received treatment upon exiting the game and was hobbling around the clubhouse when asked how he was feeling.
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"Not good," Nunez said. "I don't know how bad it is. They say they're going to tell me tomorrow first thing in the morning, so hopefully it's not bad and I can get ready to get back."
Nunez is out of options, so he can't afford to miss much time should he want to remain in consideration for a bench job with the club. He was impressing early in a small sample size, going 2-for-2 in Friday's opener and walking twice with as many stolen bases as the DH on Saturday.
"It's never a good time to get hurt, whatever position you're in," he said. "But to me, I just have to put my mind on getting better and get ready to get back into games."
Prospect Sheldon Neuse drew the start at third on Saturday and will be there again Sunday. Utility man Chad Pinder will also be utilized at the hot corner until health returns to the position.
Cotton, Triggs make spring debuts
Jharel Cotton wasted no time making an impression this spring -- quite literally.
The right-hander not only fanned five of his seven batters in his Cactus League debut Saturday but did so at a hastened pace.
"Last year, my tempo was kind of slow," Cotton said, "so this year I'm trying to just work faster to try to get the ball and go, don't give the hitter enough time to get themselves settled."
"That's one of the things we want him to do," Melvin said. "Sometimes he thinks a little too much and takes a little too long."
Cotton's confidence often wavered last year, and his overall performance was uninspiring: he pitched to a 5.58 ERA in 24 starts over two stints with the A's, allowing 28 home runs across 129 innings as a rookie.

Along the way, Cotton lost faith in his changeup -- considered one of the best in baseball when working properly.
On Saturday, it was back. Cotton's lone blemish was a walk.
"Everything was working," Cotton said. "I think today set the tone for my fastball-changeup combo.
"I felt like last year the confidence wasn't there throwing the pitch and this year I told myself, good or bad, I'm throwing that pitch, and it's going to be good no matter what. I'm just building that self-confidence while I'm on the mound. I had that mentality of, my stuff is better than yours and you're not going to hit my stuff."
Cotton pitched in relief of right-hander Andrew Triggs, both in competition for three open rotation spots. Triggs, who was back on the mound for the first time since June 9 after working his way back from hip surgery, was on the hook for three runs on three hits -- including a two-run homer from Frenchy Cordero -- and one walk over 1 2/3 innings. He struck out two.

"Overall, in terms of health and how it felt coming out of my hand, it felt really fantastic, so I'm really pleased with today in spite of some of the stuff that might stick out in the line," Triggs said. "I feel I executed my pitches for the most part."
Up next
A's top pitching prospect A.J. Puk will be on the mound at the start of Sunday's 12:05 p.m. PT matchup with the visiting Royals at Hohokam Stadium.

Rotation candidate Daniel Gossett was originally in line for the start, but back tightness will keep him from game action. Enter Puk, who was scheduled to appear in the game, anyway. Relievers Ryan Buchter and Liam Hendriks are also set to make their spring debuts.