Reynolds, who signed a one-year, $2 million free agent contract in the offseason, hit a three-run homer in the third inning.
''It feels good to barrel a ball up and see some results from all the work we've been putting in this spring,'' said Reynolds, who hit a total of 60 homers for the Orioles in 2011-12. ''Obviously it helps the confidence a little bit. I hope this one carries over into the coming weeks and into the season.''
Tony Cruz doubled and singled for St. Louis, making him 5 for 8 in exhibition play.
Cardinals starter Jaime Garcia gave up one run and two hits in four innings.
In a three-way competition to become the Cardinals' fifth starter, Garcia struck out five.
''We saw sinkers in the dirt, guys are swinging and missing, that's just different stuff than anybody else has,'' Cardinals manager Mike Matheny said. ''He had a real nice slider working today. He threw some strike curveballs. We saw changeups. It was a good outing.''
Norris didn't fare nearly as well. He didn't get out of third inning, allowing three runs and four hits with three walks and a hit batter.
''Fastball command obviously is something I need a lot more work on, but that's something we get out of camp,'' said Norris, who threw 28 of his 54 pitches for strikes. ''But coming out of there healthy was the No. 1 key for me again.''
Baltimore touched Garcia for a run in the first when Jimmy Paredes doubled home Jayson Nix.
Orioles: Norris allowed his second home run of the spring. He surrendered 20 last season and has given up 20 or more in a season three times in his career.
Cardinals: Ace Adam Wainwright threw a bullpen session against live hitters on a back field before the game. He's recovering from an abdominal strain early in camp and wants to make his exhibition debut soon, but has yet to be cleared for full participation. ''I've thrown two live BPs now - usually that's what you do before a game,'' he said.
Orioles: C Matt Wieters, recovering from elbow ligament replacement surgery, is scheduled to make his 2015 catching debut on Tuesday. He's hitless in 20 at-bats as a DH.
Cardinals: Matheny said CF Jon Jay, who underwent offseason wrist surgery, is progressing but remains a few days away from making his first Grapefruit League appearance. ... RHP Lance Lynn is scheduled to throw a bullpen session in the coming days and won't make his second spring start until Wednesday at the earliest. Lynn left his first outing with hip soreness.
John Lackey will make his spring debut on Monday against Detroit. Lackey is proceeding under a relaxed spring program.
Despite reassigning pitcher Eddie Gamboa to Triple-A, manager Buck Showalter expects the knuckleball pitcher to eventually make an impact. Showalter said Gamboa's knuckler is already better than 2012 NL Cy Young Award winner R. A. Dickey's was at this point in his development.
Orioles: Ubaldo Jimenez had a rough spring debut, then fared a bit better in his next start. He pitches against Toronto.
Cardinals: Projected minor leaguer Zack Petrick will start on Saturday against Miami's Mat Latos, who will be making his spring debut.
Link to box score: St. Louis (5-3) 8, Baltimore (3-8) 2