Although Colletti didn't mention Tanaka by name, he said, "If something else comes our way, we'll take a look at it. I'm not going to close the door on any more starters."
Including Haren, whose one-year, $10-million deal is now official, the Dodgers have five starting pitchers under contract for next season. That doesn't include Clayton Kershaw, who is eligible for salary arbitration.
But Chad Billingsley and Josh Beckett are recovering from major operations, with Billingsley expected to be unavailable until at least May. Colletti pointed out that the Dodgers broke camp this year with eight starting pitchers, only for injuries to wipe out their surplus of arms within weeks of opening day.
Tanaka could be auctioned as early as next month, provided Major League Baseball and Nippon Professional Baseball reach agreement soon on how non-free-agent Japanese players can move to the United States.
The Dodgers also could look to trade for David Price, who is expected to be made available by the Tampa Bay Rays.
Even with the Dodgers stockpiling pitchers, Haren said he isn't concerned about his place in the rotation. He said Colletti told him the team intends for him to be one of its five starters.
"I'm not going to be looking over my shoulder," Haren said.
His one-year deal allows him to return to his native Southern California after spending this season with the Washington Nationals. Haren makes his off-season home in Orange County, where his family remains during the season.
If Haren pitches 180 innings, he will have a player option for 2015 worth another $10 million. He could earn an additional $3 million each season in performance-based incentives.
From the Dodgers' perspective, Haren represented the rare pitcher on the free-agent market who could be signed to a short-term deal. The Dodgers already have eight players signed through the 2017 season and beyond — a figure that would increase if they signed Kershaw or Hanley Ramirez to extensions, or landed Tanaka.
"There's obviously a handful of pitchers that are looking for long-long-term deals," Colletti said.
The price of pitching on the free-agent market has been abnormally high this winter.
Tim Lincecum re-signed with the San Francisco Giants for $35 million over two seasons. Jason Vargas, who has a career earned-run average of 4.30, signed a four-year, $32-million deal with the Kansas City Royals.
Even pitchers recovering from injuries are landing significant deals. Tim Hudson, who fractured his ankle in July, received a two-year, $23-million contract from the Giants. Josh Johnson had an elbow operation but will be paid $8 million next season by the San Diego Padres.
Haren, 33, also faced questions about his health; there was concern around baseball about the condition of his hip and back. Plus, he was coming off a season in which was 10-14 with a 4.67 ERA.
Haren acknowledged he was "a little bit" surprised by the health of the market.
"The numbers out there, the millions of dollars getting paid is ridiculous," Haren said.
But Haren noted that television revenue is increasing and that pitching is always in short supply.
The Dodgers liked Haren not only because they could sign him to a one-year deal, but also because they didn't have to forfeit a draft pick to do so. Pitchers such as Ervin Santana and Ubaldo Jimenez who rejected qualifying offers from their former teams — basically, one-year deals for $14.1 million — will cost the teams that sign them a first-round selection in the June draft.
"I don't think we ever want to lose a pick," Colletti said.
Unless there's a radical change in the posting system, Tanaka wouldn't cost a first-round pick, either.