"I know they're using my picture and everything to promote the All-Star Game, but I have never heard that," Pujols said after Thursday's 7-4 win over the Chicago Cubs.
Pujols will join former Cardinals great Ozzie Smith as official spokesmen for the All-Star FanFest, to be held July 10-14 in downtown St. Louis.
The Home Run Derby announcement was made Thursday.
"When is the All-Star Game, six months from now?" Pujols asked about the July 14 game, to be held at Busch Stadium. "If my elbow's not healthy, I'm not doing it."
The Home Run Derby is July 13 and will be televised live on ESPN.
MLB said more than 80,000 tickets for the All-Star FanFest had already been sold, about 7,000 ahead of last year's record-breaking attendance at the old Yankee Stadium.
Information from The Associated Press was used in this report.