How long will bad back keep Angels’ Erick Aybar out?

Next to Mike Trout, shortstop Erick Aybar is the player the Angels can least afford to lose to injury, and not just because they scrambled in his absence to piece together an infield in the ninth inning of Thursday night’s 7-6 comeback win over the Royals.

The switch-hitting Aybar is a durable veteran who is hitting .273 and provides reliable and sometimes superb defense, and the Angels have no one on their team or in the minor leagues who can replace him.

But they will have to make do without him for at least a couple of days after Aybar injured the left side of his lower back while diving in the infield dirt to catch Alexei Ramirez’s fifth-inning flare in Wednesday night’s 3-2, 13-inning loss to the Chicago White Sox.

Aybar played the whole game, but the back flared up in batting practice Thursday, and he was scratched from the lineup. Manager Mike Scioscia listed Aybar as day to day.

“I felt it then, a little bit, but you’re warm, and with the adrenaline, it didn’t bother me,” Aybar said, referring to Wednesday night’s dive. “When I iced it after the game, it was bothering me. When I woke up, it wasn’t bothering me.

“When I went to the cage and did the first few swings, it was fine. And then in the second round [of batting practice], that’s when it grabbed me.”

Aybar is known for his grit and playing through pain, but when asked when he’d return, he said, “I’m not sure … I’ll see how I feel tomorrow.”

Could he go on the disabled list?

“I can’t say right now,” Aybar said. “It’s tight, so it hurts a little bit, but let’s see tomorrow.”

Scioscia said no roster move was imminent, so the Angels will go with Taylor Featherston, who has improved defensively and has a strong arm but is hitting .126, at shortstop for now.

Under the knife

C.J. Wilson informed the Angels on Thursday that, as expected, he will undergo surgery to shave down bone spurs in his elbow, a procedure that will sideline the left-hander for the rest of the season but shouldn’t affect his availability for 2016.

The rotation is deep enough to absorb his loss this season, but it will probably prevent the Angels from trading Wilson until next spring or early next season, after he shows he is fully recovered and has regained the form that made him durable and relatively dependable for the last five years.

Wilson is guaranteed $20 million in 2016, the final year of his five-year, $77.5-million deal. But with Jered Weaver under contract for one more year, four capable starters in Garrett Richards, Hector Santiago, Matt Shoemaker and Andrew Heaney, left-hander Tyler Skaggs returning from surgery and Nick Tropeano at triple A, Wilson is expendable.

The Angels discussed Wilson in trade talks this summer, and they could use the savings from his contract to pursue offensive help this winter.

mike.digiovanna@latimes.com