PITTSBURGH -- The Pirates began clearing space on their 40-man roster on Monday by outrighting five players -- pitchers Brian Burres, Aaron Thompson and Kevin Hart and infielders Brandon Wood and Steve Pearce -- to Triple-A. All five have the option to declare free agency and are expected to do so.

None of the moves come as a particular surprise, though the announcement does reduce the number of arbitration-eligible players on the Pirates' roster from 11 to nine.

Both Wood and Pearce were going to be eligible for the first time this winter, but the Pirates did not plan to tender either a contract by the Dec. 12 deadline. By parting ways with the two players, the Pirates open up roster space that can be filled by new signees or prospects the organization wants to protect from the Rule 5 Draft.

An eighth-round pick by the Pirates in the 2005 First-Year Player Draft, Pearce struggled to cement himself as a Major League player largely because of injuries. He made the club's Opening Day roster for the first time in '11 but appeared in only 50 games. A right calf tear, and later a broken right index finger, cost Pearce much of the season.

In parts of five seasons with Pittsburgh, Pearce hit .232 with nine homers and a .302 on-base percentage in 185 games.

Wood, whom the Pirates claimed off waivers in April, served primarily in a backup role this season. In 99 games, he batted .220 with a .277 on-base percentage. A former top prospect in the Angels' system, Wood finished with 16 extra-base hits.

Burres' only stop in the Majors in 2011 came in September. He spent the rest of the year pitching out of the Triple-A rotation. The lefty made five appearances (two starts) in the final month of the season and allowed six earned runs on 12 hits in 14 innings.

He has proven to be a decent Triple-A depth option for the past two seasons, but was not expected to crack the Major League rotation in 2012.

Thompson made his Major League debut in an Aug. 24 spot start for Pittsburgh this season. He also appeared in three games in relief in September. Thompson, 24, allowed six earned runs on 13 hits in 7 2/3 innings.

Hart's tenure in Pittsburgh, which began when he was a part of a 2009 non-waiver Trade Deadline deal, has been marred with injuries. He hasn't made an appearance with the Pirates since that '09 season. He underwent right shoulder surgery in May 2010 and never regained enough shoulder strength to pitch competitively this year.

The Pirates have not ruled out re-signing any of the five players to a Minor League deal this offseason. The roster moves were announced just hours after the Pirates cleared four other roster spots by declining to exercise club options on Ronny Cedeno, Paul Maholm, Chris Snyder and Ryan Doumit.