The Pirates are on the verge of signing catcher Ryan Doumit to a multiyear extension, and it could happen within the week, according to a source directly involved in the negotiations.

But negotiations with another core player, center fielder Nate McLouth, have gone much differently, with agent Mike Nicotera last night confirming that the chance of achieving a multiyear extension is "close to dead." The parties now are working on a basic one-year contract, the type most commonly arranged for players eligible for salary arbitration.

"There's a pretty stark difference between how we evaluate what Nate has done and what we believe his future will be, and their evaluation of that in terms of placing a dollar value on it," Nicotera said. "When that's the case, it's very difficult to reach an agreement."

The Pirates generally do not comment on ongoing negotiations.

Doumit, McLouth and starter Paul Maholm each is first-time eligible for arbitration, but the Pirates -- in keeping with management's precedent for core players -- decided instead to pursue multiyear extensions. From the team's standpoint, this approach can offer cost certainty through the three arbitration years. From the player's standpoint, it guarantees money.

With or without extensions, though, the team controls the player's rights through arbitration for those three years, after which he can become a free agent. In McLouth's case, that means he will remain the Pirates' property -- extension or not -- through 2011.

"And Nate's fine with that," Nicotera said. "He doesn't mind having a one-year deal. We're very confident in what he'll be able to do."

McLouth had a breakout 2008, batting .276 with 26 home runs and 94 RBIs while winning the Gold Glove in center field. He made $425,500, which was $35,000 above Major League Baseball's minimum wage.

Nicotera was asked if the Pirates' view of McLouth as a center fielder or corner outfielder -- management has acknowledged that top prospect Andrew McCutchen could take over in center someday soon -- affected the disparity in perceived value.

"No," Nicotera replied.

Nicotera did not divulge specifics, but multiple sources confirmed the parties never were in the same stratosphere in terms of dollars.

There was no immediate word on the terms or length of Doumit's contract, but it could cover all three arbitration years, and it surely will result in an exponential raise over the $412,000 he made this past season while batting .318 with 15 home runs and 69 RBIs.

The Maholm negotiations are ongoing, but there was no firm word on the status.

Also yesterday, director of player development Kyle Stark said the Pirates have three prospects facing injury issues heading into 2009:

• Starter Bryan Morris, perhaps the main piece in the Jason Bay trade, is expected to miss the opening of his season at Class A Charleston because of offseason surgery to address a lingering big-toe injury. Morris has no issue with his elbow, which was surgically repaired while in the Los Angeles Dodgers' system.

"The toe bothered Brian even before the trade in July, and it finally was taken care of," Stark said.

• Starter Brad Clapp, who went 3-7 with a 3.32 ERA in low Class A, had major reconstructive elbow surgery and will miss all of 2009.

• Reliever Tom Boleska, who had a 2.20 ERA in 24 Class A appearances, should miss time because of a strained oblique.

Nine pitchers and two position players off the 40-man roster are participating in the voluntary four-day conditioning camp in Bradenton, Fla., that concludes today. The pitchers are Ian Snell, Tom Gorzelanny, Jeff Karstens, Ross Ohlendorf, Phil Dumatrait, Matt Capps, Sean Burnett, Jeff Sues and recent Rule 5 draft pick Donnie Veal. The position players are outfielders Brandon Moss and Nyjer Morgan.

Moss, recovering from knee surgery, remains on pace to participate in spring training.

NOTES -- The field of suitors for free-agent reliever Derrick Turnbow has narrowed to five, and the Pirates remain among them, according to a source directly involved in the negotiations. One large-market team has offered a major league contract, but the Pirates have not. Turnbow, whose 2008 was cut short by shoulder trouble, is scheduled to throw for scouts in mid-January, but a signing could take place before then. ... The Pirates have made a minor league contract offer to free-agent reliever Chris Bootcheck, formerly of the Los Angeles Angels, but the team said that no agreement has been reached. ... The Pirates signed catcher Steven Suarez, 26, to a minor league contract.

Dejan Kovacevic can be reached at dkovacevic@post-gazette.com.