The trading season is here, and the Dodgers are open for business. The modus operandi is the same as last summer: a lot to offer in the way of money, not a lot to offer in the way of prospects.

The Dodgers might have even fewer top prospects available than they did last summer, meaning the payroll of the most expensive team in baseball history figures to go up.

After operating the Dodgers in the purgatory of bankruptcy, when the team needed loans to make payroll and the buzzword for trades was "cash-neutral," General Manager Ned Colletti can spend freely for the second consecutive summer.

"We're going to deal where we can, to try to make us better," Dodgers President Stan Kasten said. "I like our rotation. I like our lineup. Our bullpen has struggled. Ned has been looking at ways to improve that."

The Dodgers have been linked most prominently to starting pitchers, including Ricky Nolasco of the Miami Marlins and Matt Garza of the Chicago Cubs. The Dodgers have talked to the Cubs about reliever Carlos Marmol, who was designated for assignment last week, but they also are looking at higher-quality relievers.

The Dodgers are 3 1/2 games out of first place in the National League West. They open a series in Colorado on Tuesday, the first of nine consecutive road games against division rivals.

Kasten, speaking before word of the Marmol discussions surfaced Monday, noted that the Dodgers had not acquired or signed players with long-term contracts that extend beyond age 36.

That could be more relevant in the off-season. The top player eligible for free agency this fall is New York Yankees second baseman Robinson Cano, who turns 31 in October. If the Dodgers pursue Cano and hold to their policy, they would not offer a contract beyond six years.

Kasten declined to talk about specific players but reiterated the policy.

"We feel comfortable at 36," he said.

Although the Dodgers could take on $260 million in contracts from the Boston Red Sox in an instant — the price to acquire Adrian Gonzalez, Carl Crawford, Josh Beckett and Nick Punto last August — the minor league rebuild intended to make such trades unnecessary is coming along slowly.

"We've made progress," Kasten said. "I have to admit that the minor leagues are far away from where we need them to be. That is the reality. We don't have a lot of high-end prospects at the top."

Of the Dodgers' top 10 prospects in 2011, as ranked by Baseball America, five have been traded, one is injured, two are on the Dodgers' roster and two — pitcher Zach Lee and shortstop Dee Gordon — are in the minor leagues.

The Dodgers last summer swapped five pitching prospects — Rubby De La Rosa and Allen Webster in the Red Sox trade, Nathan Eovaldi to Miami in the Hanley Ramirez trade, and Josh Lindblom and Ethan Martin to the Philadelphia Phillies for outfielder Shane Victorino.

When Baseball America ranked the game's top 100 prospects earlier this year, the only Dodgers included on the list were outfielder Yasiel Puig and pitcher Hyun-Jin Ryu, international free agents the club spent more than $100 million to sign. Now, both are stars in L.A. Ryu never played in the minors.

The players currently ranked atop the Dodgers' minor league system are Lee and outfielder Joc Pederson, both at double-A Chattanooga, and infielder Corey Seager, at Class-A Great Lakes.

Kasten, speaking generally, said the Dodgers had no interest in trading any of their few top-tier prospects for a veteran whose contract expires when the season ends.

"If it's for a piece that would be a piece we could keep for the long term, you'd have to look at it," Kasten said, "but certainly not for a rental."

Kasten said he believes it takes three to five years to rebuild a minor league system. The new owners have invested heavily in scouting, particularly in international scouting.

"It will pay off, but it takes time. One great example right now is Julio Urias," Kasten said, referring to a 16-year-old left-hander signed from Mexico last year and pitching at Great Lakes this year. "Even he is three years away at the earliest. But that was a product of great scouting.

"There are no shortcuts. I also think the direction we pursued last year — established veterans, looking at big free agents — we are going to move away from that.

"I know people think we are in this deal, in that deal, and in any deal. That is not what the next phase of this franchise requires."

In the meantime, at the halfway point of the first full season under new ownership, the Dodgers have a record of 38-43.

"Obviously, we were held back by injuries," Kasten said. "If these things even out, we should be looking forward to a fantastic run of good luck."

bill.shaikin@latimes.com

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