The Phillies are interested in the top available relievers — specifically lefties Zach Britton and Andrew Miller — but could also explore the trade market.

Over Thanksgiving weekend, MLB.com's Jon Morosi reported the Phillies and Braves have expressed interest in trading for Mariners closer Edwin Diaz.

Let's get the caveats out of the way. This time of year, almost all teams are discussing all available players. Terms like "interest" can mean a variety of things. It could mean genuine interest, or it could mean a team has simply placed a phone call about a player it probably won't be able to acquire.

Phillies or not, Diaz is a safe bet to be traded this offseason. The Mariners are in sell-mode, and he's coming off a career year he may never be able to duplicate. Diaz led the majors with 57 saves in 65 attempts, striking out 124 in 73⅓ innings with a 1.96 ERA and 0.79 WHIP. Selling high is clearly the move for a team that has already dealt James Paxton this offseason.

All Diaz needs to succeed is his fastball-slider combination. His fastball has averaged exactly 97.3 mph in each of his three big-league seasons, with his slider picking up velocity and now just a tick under 90. He hadn't previously been as dominant as he was in 2018, but the pure stuff should give an acquiring team confidence that Diaz — 25 in March — will be a top reliever the next four seasons.

 

Diaz cannot become a free agent until after the 2022 season, which is huge for the Mariners because it means they can ask for a ton in a trade. They have a young, elite player at his position under team control for 2019, 2020, 2021 and 2022. 

The Mariners would be fully within their right to try for Sixto Sanchez, the Phillies' most exciting and highest-ceiling pitching prospect. If that sounds like an unreasonable asking price, it's really not when you consider the value Diaz could bring a team relative to his cost the next four years. You're not just getting a top-level closer — you're getting him for about one-third of the price the top free-agent relievers will command.

Should the Phillies do that? No, in my opinion. You don't trade a top starting pitching prospect for a closer unless you have a strong rotation and are a piece or two away from winning a title. For the Phils, there would be the added benefit of keeping him away from the Braves, but that's still not a reason to trade away one of your best young assets in a win-now move.

If the Phils feel more comfortable adding a top reliever via trade than free agency, they should set their sights a bit lower. Think back to their own trade of Ken Giles to the Astros in December 2015. Giles was coming off two very good seasons and, like Diaz, was cost-controlled. Giles wasn't quite at Diaz's level though, and as a result, the centerpiece of the Phillies' return was Vince Velasquez, not someone in the tier above like Lance McCullers Jr.

That is a more logical trade for a team in the Phillies' position. Potential trade fits could include Cleveland's Brad Hand, Arizona's Archie Bradley and Brad Boxberger and San Diego's Kirby Yates. All are above-average relievers ranging from good to great and all would cost less to acquire than Diaz.

And, again, the free-agent market is stocked with late-inning bullpen help. A lefty like Britton or Miller makes the most sense to improve the Phillies' relief corps, though any of Craig Kimbrel, Adam Ottavino, David Robertson and Jeurys Familia would represent an upgrade as well.

The Phillies will find the bullpen help they need this offseason and they can find it without selling the farm.

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