Sen. Claire McCaskill (D-Mo.) took to Twitter this weekend to defend her appearance at a St. Louis Cardinals game.

The first-term senator said she does not like to mix sports and politics, but that she is showing up for a good cause.

McCaskill linked to a post on her personal blog, saying that she is doing an appearance for superstar first baseman Albert Pujols' charity.

"I have always said sports and politics don’t mix," she wrote. "I have always known that the last thing sports fans want is to see a bunch of politicians shilling for votes at games. So I’ve always understood when they get booed. The way I see it, those elected officials who turn up on the field deserve to get booed."

But, she said that she was invited to honor the Albert Pujols Foundation at the game.

"I’m really looking forward to being with them today, even if it breaks my self imposed rule of never appearing on the field at a sporting event. Honoring their work is worth some booing," she wrote. "So if you’re at the game today boo to your hearts content at me, but make sure you cheer your hardest for the Pujols family and what they do for St Louis."