However, Mattingly made a point to say he only wants players who want to be in Los Angeles.
"If they don't want to be here, then I don't want them," Mattingly said.
The manager wasn't spiteful toward the 13-year veteran Lee, who has a limited no-trade clause. He was understanding of a player not wanting to be moved if he is comfortable in a situation because of kids or family -- or a cattle ranch in Lee's case. But Mattingly was insistent that he only wanted players who were determined to come and help the Dodgers make the playoffs and win the World Series.
Lee expects to make a decision by Sunday whether he'll accept a proposed trade that could include Dodgers pitching prospect Garrett Gould.
Gould, who is ranked by MLB.com as the team's No. 10 prospect, was scratched from his Friday start for Class A Rancho Cucamonga.
Lee, 36, is hitting .285 with five homers and 29 RBIs and has struck out just 17 times in 242 at-bats.
Mattingly said the team's pursuit of a first baseman like Lee isn't about a lack of patience regarding James Loney but rather a realization the team needs to get better in certain spots.
"You have to realistically look at production we're getting and how do we improve that," Mattingly said. "If anything, you try to improve your club as much as you can and I think as we look at our club, you look at areas where we need to improve."
"There are positions we're not happy with. For us to get where we want to go, we have to get better."
Loney is hitting .236 with two home runs and 21 RBIS in 74 games this season. He is 1-for-27 in his last 10 games and has been replaced by Juan Rivera at first base often. He wasn't in the lineup for Saturday's game against the Mets.
Mattingly said positions like center field, right field and second base are areas where the team is stable. But he said general manager Ned Colletti is working tirelessly to improve the club at other positions for both the short and long term.