Pujols started the last two games at designated hitter while nursing a groin injury, but the 35-year-old was cleared to play the field pregame.
"It's still bothering me a little bit, but as long as I feel OK to play, I'm going to be out there," Pujols said. "It could be worse, and I've played with worse things than that."
Brown -- a 26-year-old former first-round pick by the Giants -- was selected off waivers from the Cardinals on April 22, but the Angels needed to designate him in order to make room on the 40-man roster for Ibarra.
Ibarra, signed to a Minor League contract in the offseason, gives the Angels three lefty relievers, along with Jose Alvarez and Cesar Ramos. Converted to the bullpen three years ago, Ibarra posted a 1.93 ERA in Double-A and Triple-A in 2013, then had a down year at those levels in 2014, compiling a 4.22 ERA, a 1.48 WHIP and a 2.07 strikeout-to-walk ratio in 40 appearances.
The Angels watched Ibarra struggle in Spring Training, then moved him to the other side of the rubber, saw his fastball play up and his slider improve, then watched it translate to the Pacific Coast League, where he posted a 2.25 ERA and struck out 29 batters in 24 innings.
Ibarra was informed of his first big league callup at 10:30 p.m. local time in Memphis, Tenn., on Sunday -- in the final hours of his 26th birthday.
"Really happy to be here," Ibarra said. "I was really surprised."
• Mike Morin, nursing an oblique strain for the last eight days, continues to get treatment and should be playing catch by the end of this week. At that point, though, the 24-year-old right-hander will have to make an entire throwing progression and go out on a rehab assignment. Morin said "it's just going to depend on how my body reacts day-to-day."
• Right-handed reliever Cory Rasmus, in the late stages of his recovery from surgery to repair a core injury in March, was recently shut down from throwing to hitters in Arizona because of back stiffness. Scioscia said it wasn't serious and Rasmus is back to throwing to hitters.
• Tyler Skaggs, who will spend the season recovering from Tommy John surgery, played catch from 150 feet on Monday and said it "went really well." Skaggs will throw from that distance four days a week and plans to get off a mound in three weeks.
• The Angels hosted 1,900 at-risk students as part of an ongoing effort to keep children out of gangs. The kids -- representing the largest group to attend an Angels game under the organization OC Grip -- got the invitation as a reward for improved school attendance and behavior. Hector Santiago and Kole Calhoun were among the Angels who spoke to them pregame.