La Russa came out of the dugout during Thursday's 2-1 loss to check on Chris Duncan after the left fielder slid into the wall trying to make a catch. Duncan was fine, and La Russa retreated to the dugout amid loud cheers.
The 62-year-old manager was arrested early Thursday after police in Jupiter said they found him at a stop light, asleep at the wheel of his SUV. In a brief statement after the game, La Russa called the arrest an "embarrassment" and apologized.
"I regret it, take responsibility and I'm not sure there is anything else I can say," he said.
As for the game, Duncan said he a bit shaken up by the collision.
"I'm OK," he said. "It just startled me a little bit."
No. 1 starter Chris Carpenter struck out six in six innings, allowing one run, four hits and a walk.
Marlins starter Dontrelle Willis pitched 6 2-3 shutout innings, allowing three hits. He struck out five and walked two.
"I expect a lot out of myself," Willis said. "I've been feeling strong all spring."