9:52am: Yahoo’s Jeff Passan tweets that the trade is at the finish line, and a deal is “imminent.” MLB.com’s Joe Frisaro reports that the Marlins are seeking a pair of quality prospects in exchange for Phelps (Twitter links). Fellow right-hander AJ Ramos is not a part of this trade and is being discussed with multiple other teams, Frisaro adds.

9:12am: MLB.com’s Jon Morosi tweets that the two sides are actually “fairly close” to completing a trade that would send Phelps to Seattle.

8:56am: FOX’s Ken Rosenthal also hears the two sides are talking but says there’s no match to this point, as the Marlins don’t love the Mariners’ minor league system (Twitter link).

8:48am: The two sides are indeed discussing a possible Phelps swap, Feinsand tweets. Nothing between the two sides is done just yet, as talks are apparently ongoing.

Phelps, 30, would give Seattle a setup arm that can be controlled through the 2018 season. He’s earning $4.6MM this season on the heels of a breakout 2016 campaign and has worked to an impressive 2.69 ERA with 11.1 K/9 against 4.0 BB/9 through 133 2/3 innings dating back to Opening Day 2016. Phelps also has a 46.4 percent ground-ball rate in that time, which checks in a couple of percentage points above the league average, and he’s working with a career-best 94.4 mph average fastball velocity in 2017 as well.

July 20, 1:02am: Seattle “had been working on” a scenario involving David Phelps of the Marlins, Feinsand tweets, though it’s not yet clear if he’s the player that is currently nearing a uniform swap.

July 19, 12:37am: The Mariners are closing in on a trade to pick up a relief arm, according to MLB.com’s Mark Feinsand (via Twitter). It’s unclear at this point just who could be heading to Seattle, or even whether it’s a significant trade.

With a victory today, the M’s have pulled back to .500 and are firmly in the Wild Card hunt — though the AL West is still a one-horse race. While the club arguably is most in need of rotation upgrades, rare is the team that couldn’t improve by adding another piece to the bullpen.

In Seattle’s case, the current unit has produced middle-of-the pack overall results (4.07 collective ERA), though the metrics suggest that the true performance hasn’t been quite that good overall. Closer Edwin Diaz has had his peaks and valleys, though he has been firmly on the upswing during a dominant July. Indeed, that holds true of the entire relief corps.

The youthful Diaz could be bumped into a roving role if GM Jerry Dipoto aimed big. Setup man Nick Vincent has been the team’s best reliever, but perhaps could stand to be paired with another quality late-inning arm in front of Diaz. It’s conceivable that a big lefty would make sense. Southpaws James Pazos and Marc Rzepczynski have generated good results in the earned run department, but the former has been knocked around of late and the latter has increasingly shown worrying control issues.

Or, of course, the M’s could simply be bolstering their depth with a relatively insignificant addition. Given Dipoto’s sometimes frenzied trading history, it’s anyone’s guess just what this apparently pending transaction might represent.