Angels successfully employ an ‘opener,’ and they’ll use it again

Looking to ease pressure on an underachieving starting rotation, Angels manager Brad Ausmus employed reliever Hansel Robles as an “opener” against the Seattle Mariners on Sunday and replaced the right-hander with original starter Jaime Barria in the second inning.

Robles, making his first start in his 235th career game, retired the side in order on 13 pitches and Barria allowed one run and four hits, struck out three and walked none in five innings of an 8-6 Angels victory.

“Hansel did exactly what we hoped — he got the top of the order out,” Ausmus said. “It allowed Barria to start in the middle of the order as opposed to the top.”

Ausmus said the opener will “definitely be used as a tactic again,” but he couldn’t predict how often.

“Well, it worked today, but you can’t do it on a daily basis,” Ausmus said. “But I’m sure when there are opportunities to do it, we’ll do it to help us win games.”

The decision to follow a strategy the Tampa Bay Rays used liberally last season was spurred by concerns about a rotation that has not shown the ability to get deep into games in the first three weeks of the season.

Angels starters entered Sunday with a 6.19 ERA, the second-worst mark in baseball behind the Boston Red Sox, and threw 100 1/3 innings in 21 games, an average of 4 2/3 innings per start.

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“We had been talking about it for a little while,” Ausmus said. “It’s a way to actually extend the starter [because he] doesn’t have to face the top part of the lineup, which is generally the best part of the lineup. And Robles is one of our better relief arms. We want someone who can get those better hitters out.”

Ausmus, then a special assistant to general manager Billy Eppler, was in Angel Stadium last May 19-20 when the Rays, thin on starting pitching and heavy on effective relievers, used Sergio Romo as an opener for the first time.

Romo, the veteran right-hander, struck out the side in the first inning May 19 and was replaced by left-hander Ryan Yarbrough, who allowed one run in 6 1/3 innings of a 5-3 Rays victory. Romo started the next day’s game and struck out three in 1 1/3 innings of a 5-2 Angels victory.

The Rays went 32-23 in games they employed the strategy. They went 58-49 in games they used a traditional starter.

“At the time, I thought it was a pretty good idea, especially against our lineup,” Ausmus said. “We had all right-handed hitters at the top of our lineup. And Romo is obviously a very good right-on-right pitcher.”

Rehab report

Tyler Skaggs (left-ankle sprain) will complete at least one more rigorous bullpen session this week before being activated, but the left-hander believes he can return without a minor league start.

“I wouldn’t say I’m 1,000%,” Skaggs said, “but I feel pretty good.”

Skaggs doesn’t want to make the mistake he made last summer, when he pitched through a left-groin injury and made several trips to the disabled list.

“That’s kind of why I need to be smart about this,” Skaggs said. “I need to really be confident in it. . . . I’ve gone down this road before. It’s tough to get major league hitters out when you’re not 100%.”

Left fielder Justin Upton’s left foot remains in a walking boot as he recovers from a turf-toe injury that has sidelined him since late-March. He is not expected to return until June. “I know I’m making progress,” Upton said. “Slowly, but surely.”

mike.digiovanna@latimes.com

@MikeDiGiovanna