The 28-year-old fouled a pitch off the top of his foot against the Yankees last weekend, but has never felt a pain like he did Saturday. The pain, he described, went all the way up to his head.
"It's still sore," Aybar said. "But we're going to wait two days or so and see what happens."
Segura, called up for the first time in his career, will serve as additional depth, with Maicer Izturis being the starting shortstop until Aybar returns. The Angels couldn't recall Andrew Romine because it hasn't been 10 days since he was sent down.
Segura can play both middle-infield positions.
"Just for some depth right now, and we'll evaluate where we are," Angels manager Mike Scioscia said. "If Erick goes on the DL, then obviously it'll be a different scenario. But right now, we need more infield coverage in the next couple days, until we see how Erick sets up."
In 94 games in Double-A this season, Segura batted .294 with seven homers, 40 RBIs and 33 stolen bases. He is ranked the No. 1 prospect in the Angels organization by MLB.com and No. 45 overall in the Major Leagues.
Segura was taken out of Saturday's game in Arkansas and told he was being called up in the seventh inning after going 2-for-3 with a triple. He thought he might have been traded, but got some exciting news instead.
"The first thing that I did, I called my mom," Segura said. "She was so happy and cried. I think she was going to have a heart attack. I said, 'Mom, it's OK. I'm going to the big leagues. This is my dream.'"
Carpenter, who was sent down to make room for Segura, had a 3.55 ERA in 25 appearances with the Angels this season. He threw four innings in relief of starter Ervin Santana on Saturday, giving up one run on three hits.