"I'm really tired of watching the effort, that's for sure," Clark told 101 ESPN Radio in St. Louis on Thursday. "I'm not seeing a lack of [effort], I'm seeing a pathetic effort. These Cards fans deserve much better. That's just awful. They won't admit it, that they're quitters. If you can't put a better effort out there on the field, take 'em all out, back up the truck, ship 'em all out and get somebody in here that wants to play baseball."
Asked about the comments, La Russa first said that he prefers not to engage in a war of words.
"We've got enough problems trying to win games, and we're exposed enough for not playing better that we don't need to start having back-and-forths with anybody," La Russa said. "Because the essence of my job and our team's job is to compete this year. If we're not competing well enough, then that's where you're going to catch the heat. And you don't need anything else."
With that said, though, La Russa went on to express his feelings about what Clark had to say.
"I just don't feel like Jack has had the kind of spotless career where he can make judgments like that," La Russa said. "Whether it's our team, whether it's players, pitchers, whatever.
"I think that [quitting accusation] is real personal. That's why I'm saying something about it. That's a very offensive quote to make. I respect Jack a lot, because I think he did a good job of pulling his career together. But he had times where the evaluation from his peers -- and I wasn't his peer -- but [the evaluations by] his peers and his bosses were less than the best. So I'm disappointed that he didn't take some of that past experience, especially guys that play should know how hard this game is.
"I definitely understand if the media, the fans [don't realize that]. But a guy who has played or pitched, this is a very tough game to play. It doesn't always fall into place.
"You especially know that that's a much bigger cut than to say you're a bad pitcher or player, manager or coach. Then you're just not good enough. But when you start getting at the integrity of the competition, that's [especially bothersome]. But this is America. You've can have your opinion. We've got free speech. Have at it."