"Last year, we were sellers, so what this says is that we feel we have a chance to win," said Mattingly, whose club is waiting to hear if the Cubs will accept its offer for right-handed starter Ryan Dempster, while still pursuing a run-producing bat.
"When you're active in a positive way to fill a hole, I think it sends a message to the team that you feel you can win and it sends a message to the fan base that we're here to win."
Mattingly said that Dodgers general manager Ned Colletti has been working on deals for a month, but they generally go down to the July 31 non-waiver Trade Deadline.
Mattingly also praised the club's new ownership for making available the financial resources to pick up players with significant contracts.
"Everything is different with the new ownership; it's a new mindset," Mattingly said. "The whole environment is different. These people are saying they want to take the Dodgers back to where they were in the past, where the organization should be. It's a good feeling to know we're trying to get better. It also says a lot about the guys we have here playing, that they hung tough and kept us in it and gave us this opportunity."