UPDATE: The Mets have announced the trade.

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After various rumors suggesting the New York Mets were not going to make another trade before the MLB's Aug. 31 waiver deadline, general manager Sandy Alderson executed a deal to bolster the team's bullpen.

The Mets acquired reliever Addison Reed from the Arizona Diamondbacks, according to Adam Rubin of ESPNNewYork.com. The Diamondbacks received prospects Matt Koch and Isan Diaz from New York, reports Bob Nightengale of USA Today Sports.

Marc Carig of Newsday and Steve Gilbert of MLB.com also confirmed the deal.

The Mets have yet to announce the transaction.

New York's bullpen has been a bit unreliable beyond Tyler Clippard and Jeurys Familia, which has been a cause for concern as the waiver trade deadline was approaching. Earlier this week a source said the Mets were unlikely to strike a deal for a reliever before Aug. 31, but it's clear Alderson was a bit uneasy about the club's cast of relievers after Carlos Torres surrendered three runs in the top of the 10th inning in Friday's 6-4 loss to the Boston Red Sox.

Reed, 26, had a rough start to the 2015 season and was demoted to Triple-A in late June. However, since his return to the MLB, the right-hander owns a 1.65 ERA in 13 appearances (16 1/3 innings) and has notched four holds. He's now 2-2 with a 4.20 ERA, 1.50 WHIP and 34 strikeouts in 38 games (40 2/3 innings) this season.

Rubin reported on early Saturday that the Mets were "making progress on acquiring a reliever." The team also claimed Padres' reliever Marc Rzepczynski, but it's unlikely they work out a deal for the left-hander, says Carig.

The Mets are poised to make the postseason for the first time since 2006 and the bullpen has seemingly been their only weakness as of late. Veterans Carlos Torres and Eric O'Flaherty have not been performing well this month while the team is probably unsure how youngsters Hansel Robles, Sean Gilmartin and Logan Verrett will perform down the stretch.

The Reed deal is pending a physical.

Stay tuned for updates.