Altuve didn't foresee Correa signing with the Minnesota Twins.
"I was surprised. I wasn't expecting that," Altuve said Sunday. "Obviously we're going to miss him. He's a great player and a great guy inside the clubhouse. He was one of our leaders."
Correa reached a $105.3 million, three-year deal with the Twins on Friday night. The shortstop had been the most coveted free agent remaining on the market.
Altuve, a seven-time All-Star and the 2017 AL MVP, and Correa, a two-time All-Star, were mainstays in the middle of Houston's defense and at the top of the order since 2015. The duo helped lead the Astros to their lone World Series title in 2017 and return trips to the Series in 2019 and 2021.
A career .277 hitter with 133 home runs, Correa batted .279 with 26 homers and 92 RBIs last season and also won his first Gold Glove.
"Now that he's on another team, I'm happy for him," Altuve said. "He got a great deal. Happy for him. I know he's going to play good. He's going to make the Twins better."
Altuve, 31, said he and Correa, 27, pledged to remain close via frequent phone calls and video chats.
"We had dinner so many times," Altuve said. "We spent a lot of time in rooms together talking about different things. That's what I'm going to miss the most."
A few days before Correa's decision, Houston manager Dusty Baker tabbed Jeremy Pena the front-runner for the Opening Day start. Widely considered one of the Astros' top prospects, Pena is a career .291 hitter in the minors. He batted .287 with 10 homers in 30 games at Triple-A Sugar Land last season.
Pena, 24, and son of former major leaguer Geronimo Pena, has a locker in the Astros' clubhouse next to Altuve.
"I'm happy for Jeremy that he might get the opportunity to come and play in the big leagues and establish himself as an everyday player," Altuve said.
While Baker would have liked to have Correa in the lineup, his signing removed a bit of the fog that had wafted into Houston's camp this spring.
"Nobody likes to be in an uncertain situation," Baker said. "Everybody likes clarity."
Still, some habits are hard to break.
Players arriving at the clubhouse on Sunday morning before the Astros-Washington exhibition game saw a familiar name written into the cleanup spot on the day's lineup card: Correa.
Baker's decision to hold his major league position players out of early games this spring allowed him start Carlos' bother, J.C., at designated hitter against the Nationals.
J.C. hit .310 with nine homers and 57 RBIs last season in 101 games split between Class A Fayetteville and High Class A Asheville.
Now learning to play catcher, J.C. enjoyed a six-hit game and two four-hit games last season, his first as a minor leaguer.
"That's a lot of hitting," Baker said.
• Nationals minor leaguer Darren Baker took out the lineup card for the pregame exchange with his dad, Dusty. Darren and Dusty hugged over home plate, then posed for pictures together and with the umpires. Darren later got into the game playing second base.