UPDATE: The Mariners will also send the recently-acquired C.J. Riefenhauser (from six-player trade with Tampa Bay Rays) to the Orioles in the deal, according to Dan Connolly of the Baltimore Sun. He says the deal is not done, but it "should happen."

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UPDATE: Heyman says the two sides have struck a deal for Trumbo and Dutton as well as Greg Johns of MLB.com notes the Orioles are "likely" to get another player in addition to Trumbo. However, both say no deal is done yet.

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UPDATE: Jon Heyman of CBS Sports says the talks between the Orioles and Mariners are "heating up" and Bob Dutton of the Tacoma News Tribune reports the two sides are nearing a deal that would send Mark Trumbo to Baltimore in exchange for Steve Clevenger (the Orioles are also seeking another player in the trade).

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In the Baltimore Orioles' quest to avoid their mistakes from last offseason, the team has already gotten to work this time around. Rumors suggest they've already made an offer to one of their impending free agents and are attempting to do further work on the trade market.

According to Dan Connolly of the Baltimore Sun, the O's have made a "competitive" bid for reliever Darren O'Day, who has spent the last four years in Baltimore. Previous rumors suggested the right-hander was seeking a three- to four-year deal between $28 million and $34 million.

"Although negotiations have been ongoing, it's believed to be the first formal offer made by the Orioles to O'Day since the season ended," writes Connolly.

"Indications are that O'Day is currently weighing his offers and there is a possibility he could agree to a contract with a team before the winter meetings start Monday in Nashville, an industry source said.

"The Orioles might not be considered the front-runners, but appear to be in the final conversations along with the Washington Nationals, Atlanta Braves and the Los Angeles Dodgers, among others."

O'Day earned his first All-Star honors in 2015 and owns a 23-8 record with a 1.92 ERA, 0.94 WHIP and 283 strikeouts in 273 games (263 innings) over the past four seasons with the Orioles. The right-hander has been one of the best relievers in the MLB over that span. Baltimore did not present him with the qualifying offer, perhaps with the belief that they had a good chance to keep him.

"O'Day has emerged as a team leader with the Orioles and has forged strong relationships with many teammates, fans and manager Buck Showalter."

As for their action on the trade front, recent reports suggest the O's are also interested in acquiring Seattle Mariners first baseman/outfielder Mark Trumbo, who is being aggressively shopped by general manager Jerry Dipoto.

"The Orioles are in the mix now for Mariners slugger Mark Trumbo, who is on the trade block," writes Jon Heyman of CBS Sports.

"The Orioles are looking for a first baseman, a DH and an outfielder or two, so Trumbo fits for them. They have been in talks with their own free agent star Chris Davis, who is their main target, but Davis is expected to blow away the Orioles' record contract with a big nine-figure deal."

Roch Kubatko of MASNSports.com confirmed the Orioles' interest in Trumbo. He also notes the team expects the Mariners will tender Trumbo a contract because he's projected to earn $9.1 million in his final year of arbitration eligibility, which Seattle likely feels is not worth the financial risk. In this scenario, the M's would non-tender Trumbo and have a couple of months to work out a more fair salary.

This would be beneficial for both the Mariners and the Orioles. If Seattle can't get rid of Trumbo, they'll be able to keep him at a much lower salary for 2016. On the other hand, his lower salary will probably make him more of a commodity on the trade market, which would help the O's, who have payroll restrictions.

Baltimore could get creative and add multiple pieces that would collectively replace Davis' power, rather than shell out an immense long-term deal for one player.

Stay tuned for updates.