SAN DIEGO -- Indications are that the D-backs are close to agreeing to a contract extension with starter Dan Haren.

"I'm pretty confident something will get done sooner rather than later," Haren said. "[The talks] have progressed so we're moving in the right direction."

The D-backs acquired Haren from Oakland in December in exchange for six prospects. Aside from his outstanding performance on the mound he was attractive to them because of his contract situation. He is slated to make $4 million this year, $5.5 million in 2009 and there is a club option for 2010 for $6.75 million.

It's not known how long the extension is for, but the club had previously discussed a three-year deal with pitcher Brandon Webb, who is also under contract through 2010. The talks with Webb were tabled last month.

"We've been talking throughout the year," Haren said. "It's progressed, but there's still a lot of things getting worked out. It's complicated, it's hard during the season because neither side can devote as much attention to it as we could in the offseason. I'm sure if talks had started during the offseason than they could have moved a lot quicker."

Haren has certainly helped his leverage with his performance on the mound so far this year. The right-hander is 10-5 with a 2.56 ERA, which leads the National League, and his 1.5 walks per nine innings are the fewest in the NL.