ST. LOUIS -- With several position players ailing, the Chicago Cubs called up 2015 first-round pick Ian Happ from Triple-A Iowa on Saturday and inserted him into the starting lineup against the St. Louis Cardinals.
Happ, 22, wasted no time making his presence felt, delivering a two-run homer in the seventh inning for his first major league hit in Chicago's 5-3 loss.
"It was a changeup -- got barrel on it, and watching it go, it had a little bit of legs to it," Happ said of the home run.
He later got the ball back from a fan.
"He's very calm and a confident young man," said Cubs manager Joe Maddon. "What you saw today was not a surprise to any of us. He's obviously an interesting young player.
"He was never overwhelmed by being here today. He put the uniform on and went out there and hit a homer."
In the fifth inning, Happ was called out for interference on a hard slide into second base. On a grounder by Anthony Rizzo, Happ slid past the bag while Cardinals shortstop Aledmys Diaz took a throw from pitcher Carlos Martinez, and Rizzo was ruled out at first because of the violation. Kyle Schwarber had scored from third base, but that run was nullified by the double play, keeping the Cardinals ahead 3-1.
"We're out there playing with a bunch of pansies right now," said Cubs starter Jon Lester. "I'm over this damn slide rule. We're all grown men out there. I told Happ in the dugout to do the exact same thing the next time. It's baseball, man."
Happ, who played right field and batted second, has impressed since appearing in his first big league spring training camp in February. He hit .383 with five home runs in the Cactus League and carried that over to the start of his Triple-A season. He was hitting .298 with nine home runs and 25 RBIs before getting called up.
"It was a fun day," Happ said of his majors debut. "Losing stinks, but to be in there and around these guys was definitely fun."
He later tweeted that the support from everyone "has been overwhelming."
Happ likely will be needed for only a few days, but manager Joe Maddon wouldn't commit to a timeline, as he has several players banged up because of various ailments. Reigning NL MVP Kris Bryant was a late scratch Friday due to a stomach ailment and was out of the lineup Saturday. Ben Zobrist (back) and Addison Russell (shoulder) are available only for pinch-hitting duties.
"How long is he [Happ] going to stay?" Maddon said earlier Saturday. "I have no idea. It could be short; it could be longer than that. I don't know."
The call-up of Happ means the Cubs' No. 1 picks from 2011-15 are on their major league roster. Their lineup Saturday included five players with less than a year of major league experience. Maddon said he isn't concerned because they're all talented, including the switch-hitting Happ.
"Go out there, have fun and compete," Maddon told his newest player.
Happ, meanwhile, was trying to slow things down for his major league debut.
"Take it in and enjoy it," he said pregame. "This is one of those situations where you might wake up tomorrow and not remember what happened."
ESPN.com's Keith Law had Happ ranked as the 63rd-best prospect in baseball entering the season.
Information from The Associated Press was used in this report.