La Russa and Pujols will join former Republican vice presidential candidate Sarah Palin as honorees for a Saturday event organized by Fox News talk show host Glenn Beck.
The Cardinals manager says his role, as well as Pujols', will be nonpolitical.
"It has absolutely nothing to do with politics," La Russa said Friday night following the Cardinals' 4-2 win over the Nationals. "Otherwise, he would not be involved. For anybody to look at it differently, they're making a big mistake. ... It's got nothing to do with politics with any issue on either side."
La Russa, no stranger to political controversy of late, will present an award to Pujols during the rally to be held on the 47th anniversary of Dr. Martin Luther King Jr.'s "I Have a Dream" speech at the site where it was delivered.
La Russa weighed in on Arizona's mandate for local enforcement of immigration law earlier this summer, when he said he supported the much-protested law that has since been put on hold by a federal judge, while Pujols has been outspoken about his opposition.
And observers quickly noted the possible conflict of interest.
"Pujols has been very vocal against SB1070 and other civil rights issues," Roberto Lovato, co-founder of Presente.org, among the organizations seeking a boycott of next season's All-Star Game in Phoenix, told the New York Daily News. "We sure hope he continues to do the right thing this weekend."
But La Russa was confident his bases were covered.
"I made the point several times: What is this about?" La Russa said Thursday, according to the St. Louis Post-Dispatch, of the rally billed as a celebration of the First Amendment and one reportedly also expected to be centered around a message of faith.
"I don't know who's going to be there, who's going to accept it," La Russa said. "But the gist of the day is not political. I think it's a really good concept, actually."
Pujols declined comment when asked about the rally before Friday's game.
Information from The Associated Press was used in this report.