Thompson’s stay is short

As expected, Trayce Thompson’s time with the A’s was short. The outfielder, brother of Warriors guard Klay Thompson, was designated for assignment Tuesday to make room for starting pitcher Trevor Cahill.

The A’s have numerous righthanded-hitting outfielders on the roster, making Thompson, who is out of options, more expendable. If Thompson clears waivers, as the team hopes, he will be sent to Triple-A Nashville. Several teams need outfielders, however, making that a somewhat unlikely scenario.

Thompson played sparingly after being acquired on waivers from the Yankees on April 5, going 1-for-7. He made a spectacular catch against his former team last Wednesday at Dodger Stadium, robbing Yasiel Puig of a homer.

“It was difficult letting him go, because he fit in really well here,” manager Bob Melvin said. “Guys like him, the coaching staff loved him, he’s a hardworking guy. Certainly, we’d love to be able to keep him in the organization.

“If not, I hope he lands in a good place and gets to actually stick somewhere and play because it’s difficult to go through this once, much less three times. You feel for him because he’s such a good kid on top of it.”

The A’s also called up reliever Lou Trivino on Tuesday, and the 26-year-old made his majorleague debut in the ninth, allowing two hits and a walk and striking out two. Trivino takes the spot of Yusmeiro Petit, who is on the emergency family leave list. Melvin said Petit has returned home to Venezuela and is expected back Saturday.

Trivino retired all 13 batters he faced with Nashville this year, striking out eight, and he impressed during the spring, putting up a 1.93 ERA.

“I’m feeling better as I go along,” Trivino said. “I kind of keep on doing what I was doing during the spring. I’ve been able to attack the zone, attack the hitter, avoid falling behind, avoid two-ball counts, and it’s been working.”

Melvin said that entering the season, the A’s had targeted Trivino as a reliever who might be up this season.

“He has a power arm, good sink and high velocity,” Melvin said, noting that Trivino’s third pitch is a changeup. “He’s someone who impressed us during spring training . ... He throws upper 90s with good movement.”

Petit has 10 appearances, tying him for the league lead, and has a 3.00 ERA. Opponents are batting .265 against him, and he has not issued a walk.