The Diamondbacks, moving aggressively to trade third baseman Troy Glaus, are in serious discussions with the Red Sox, Blue Jays, Orioles and an unidentified National League club, has learned. The Red Sox and Blue Jays are the front-runners for Glaus, according to an official from one of the interested clubs. The Sox, Jays and Orioles likely would move Glaus to first base, a position he has not played in his eight-year major-league career. Glaus, 29, has limited no-trade protection in the four-year, $45 million contract he signed with the Diamondbacks last off-season. He would need to approve a deal to the Blue Jays, according to a source with knowledge of his contract. It is not known whether the other suitors are on his no-trade list. The Diamondbacks, trying to add pitching, believe they can unload Glaus without paying any of the $32.75 million that he is owed in the final three years of his contract, sources say. The Jays offered second baseman Orlando Hudson for Glaus, and probably would be willing to part with right-hander Miguel Batista as well if they obtained another player in the deal.