Despite the perception that player-for-player trades are rare in the NFL, Detroit Lions GM Martin Mayhew may have already pulled off his fourth such deal of the offseason.

The St. Louis Post-Dispatch reported Wednesday that the Lions had swapped wide receiver Ronald Curry to the Rams for defensive tackle Orien Harris, giving both teams a minor boost at a worrisome position.

A 6-foot-3, 300-pound space-eater in just his third season out of Miami (Fla.), Harris is already on his seventh team. The Rams traded RB Brian Leonard to Cincinnati for Harris’ rights earlier this year.

Originally a fourth-round draft pick of the Pittsburgh Steelers in 2006, the 26-year-old Harris played in two games with the Browns at the end of that season, was inactive for both Buffalo and New Orleans in 2007, and played in 14 games — starting once — for the Bengals last fall.

Despite only 14 career tackles, Harris still has far more experience than Lions' fourth-round pick Sammie Lee Hill, one of the only other depth players at the position. The two will likely be the backups behind starters Grady Jackson and Chuck Darby, and will become even more valuable should Jackson, as feared, start the season with a suspension for violating the league’s substance abuse policy. The Lions tried and failed to sign veteran DT John Thornton as a free agent earlier this month.

Signed as a street free agent on April 16, Curry was made expendable when Mayhew traded for slot receiver Dennis Northcutt three weeks ago. The eight-year veteran Curry, who’d spent his first seven seasons with the Raiders, was attractive to a St. Louis team that had cut ties with both Isaac Bruce and Torry Holt in the past two seasons and is rebuilding its receiving corps with a slew of youngsters.

In the spring, Mayhew sent disgruntled quarterback Jon Kitna to the Cowboys for veteran defensive back Anthony Henry, then swapped defensive tackle Cory Redding to Seattle for linebacker Julian Peterson. Three weeks after taking over as the team’s interim GM last year, Mayhew sent wide receiver Roy Williams and a fourth-round pick to Dallas for three draft picks.

UPDATE (July 24): The Lions confirmed the trade Friday, likely after waiting for both players to pass physicals with their new organization.