Bush confirmed the plans at a White House luncheon for a roomful of Baseball Hall of Famers Wednesday, the St. Louis Post-Dispatch said.
"One of the traditions, of course, is for the president to throw out the opening pitch for baseball," Bush said. "I'm going to do so for the Cards."
The president said he wasn't as concerned work would keep him away as his pitching ability was questionable.
Saying "my arm is a little sore," Bush said he had asked advice from one of the guests, knuckleball specialist Phil Niekro, who won 318 games for the Atlanta Braves and other teams with his unpredictable floaters.
Bush is an avid fan and former part owner of the Texas Rangers. He said as president he's had the opportunity to host "a fair amount of lunches and dinners, and I have a confession to make -- this is my favorite one."
"It's kind of like having your baseball collection spread out in real life," he said.