SAN FRANCISCO -- Seeking to add a fresh arm to their overworked bullpen, the Giants called up right-handed reliever Sam Coonrod and optioned left-hander Andrew Suarez to Triple-A Sacramento ahead of Sunday afternoon’s series finale against the D-backs.

Suarez produced a quality start in his season debut with the Giants on May 20, but he struggled in Saturday’s 10-4 loss to the D-backs, giving up a career-high nine runs (seven earned) over four innings.

“He was just off,” manager Bruce Bochy said. “His first start, if you noticed, he was right there at the bottom of the strike zone with all his pitches, quality pitches, and that’s when he gets his ground balls. That pitch was just missing for him last night. He gave up a lot of hard-hit balls. He’ll continue to refine his stuff, his command and be consistent.”

Bochy said the Giants have not yet decided who will take Suarez’s spot in the rotation. Dereck Rodriguez, who worked two scoreless innings in relief on Saturday, is a possibility, though Bochy said the Giants will keep him in the bullpen for now. Tyler Beede is another option, and he bolstered his case for another look in the rotation by tossing seven innings of one-run ball in his last start for Triple-A Sacramento on Friday.

Coonrod, the Giants' No. 22 prospect per MLB Pipeline, received his first big league callup after posting a 7.00 ERA with 30 strikeouts over 18 innings for Triple-A Sacramento this season. His ERA was skewed by a rough stretch at the beginning of May, but he's pitched better of late, including Sunday, when he threw a perfect inning in his Major League debut in the Giants' 6-2 loss.

“He’s been throwing the ball very well,” Bochy said. “He’s mainly a one-inning guy, but he could go a couple for us. We need some help with our bullpen situation.”

Offense has surged across the Triple-A level following the switch from the standard Minor League ball to the Major League ball this year, and Coonrod said he felt he got back on track after beginning to throw a two-seam fastball to induce more grounders and prevent hitters from getting the ball in the air.

“The guys that played there before me told me that it was already hard, and then they added those balls,” Coonrod said. “You can tell that the home runs went up quickly. I started throwing a two-seam fastball mainly because of that. Hopefully, it would go on the ground more because if you get it in the air there, it’s easy to go out.”

A fifth-round Draft pick of the Giants in 2014, Coonrod was limited to 11 2/3 innings last season after returning from Tommy John surgery. Despite his abbreviated 2018 campaign, the Giants saw enough upside in Coonrod to add him to their 40-man roster and protect him from the Rule 5 Draft in November.

“A year ago, I was still rehabbing, so I just feel healthy now and smarter, more mature,” Coonrod said. “I’m extremely blessed. Very thankful for the opportunity.”

Worth noting

Tyler Austin hasn’t played third base since 2016 in the Minors, but he began taking ground balls at the position on Sunday morning. The Giants have been trying to find more spots for Austin, who has posted a .933 OPS in 29 games for San Francisco.

“We’re just moving him around,” Bochy said. “He wants to take grounders there. He’s trying to increase his versatility so he can find a way to get more playing time. He took some fly balls in left field, ground balls at third today.”