Pros and Cons: Should Mets trade for Merrill Kelly?

The Mets' starting rotation situation this year has been wild.

They started off with so much depth that there were questions about how they'd fit everyone in.

By the middle of the season, though, a rash of injuries had them reaching into the minors for spot-starters, pondering whether to promote their top pitching prospects, and eventually deploying bullpen games for two of the three Subway Series matchups against the Yankees in early-July.

While Griffin Canning's injury was season-ending and Tylor Megill's return is still TBD, things have normalized.

The Mets are now finally using the rotation they envisioned would be their starting five on Opening Day:

Kodai Senga
Sean Manaea
David Peterson
Clay Holmes
Frankie Montas

Beyond those five pitchers are some intriguing options in Triple-A Syracuse. There's Blade Tidwell, who has been called upon a few times in his rookie year, and two prospects who have the potential to develop into top of the rotation arms: Nolan McLean and Brandon Sproat.

Speaking earlier this month, president of baseball operations David Stearns said he was reluctant to use top prospects for spot starts -- but it's possible McLean and Sproat both debut later this summer when they're deemed ready for long-term roles.

Still, while it's nice to picture a future where McLean and Sproat are mainstays in the rotation, it's impossible to rely on them in the heat of a pennant race in what will be their first taste of the majors.

Combine that with an injury question surrounding Manaea (pitching with a loose body in his elbow) and the workload question hanging over Holmes (who has already thrown more innings this season than any other), and New York should be placing a high priority on adding another legitimate starting pitcher via trade.

Should they target Diamondbacks right-hander Merrill Kelly?

PROS

Kelly has been both effective and reliable for Arizona this season, with a 3.32 ERA (3.48 FIP) and 1.05 WHIP with 118 strikeouts in 122.0 innings spanning 21 starts.

He has allowed a career-low 6.8 hits per nine, has a walk rate right at his career level (2.7 per nine), and has gone 6.0 innings or more 13 times already this year -- the kind of length that would be huge for a Mets team badly in need of more innings from their starters.

In addition to being very good and taking the ball every turn, Kelly shouldn't be too expensive to acquire.

A free agent after the season, it's impossible to see the D-backs being able to obtain any truly elite prospects for him. In the Mets' case, that means any of their top nine or so prospects (a list that includes Jonah Tong, Jett Williams, Nolan McLean, Brandon Sproat, and Carson Benge) would be off-limits.

What Kelly has done this season also isn't an aberration. For his career, which has included four of five full seasons where he has made 27 or more starts, Kelly has posted a 3.76 ERA (3.97 FIP) and 1.19 WHIP while striking out 8.2 natters per nine.

Kelly isn't someone who profiles near the top of the rotation, but he would be a great fit for the Mets behind Kodai Senga, Sean Manaea, and David Peterson -- especially considering Holmes' likely innings limit.

CONS

Kelly's advanced stats via Baseball Savant aren't great, especially his hard hit percentage (26th percentile), and average exit velocity (19th percentile).

But his advanced numbers have never really blown anyone away, and his stuff (a legitimate six-pitch mix) continues to play up exceptionally well.

As far as what it might take to pry Kelly from Arizona, while it shouldn't require a true top prospect, the D-backs could be in an advantageous spot.

With so many potential buyers and the Diamondbacks still theoretically in playoff contention, they should be able to net a strong package in return.

While Kelly would be a nice get for New York, it can also be argued that they should be aiming for more upside here. But with bigger needs in the bullpen and center field, it's a bit hard to imagine the Mets diving head first into the deep end of the starting pitching market.

VERDICT

Whether it's Seth Lugo or Zac Gallen or Kelly, it should be an easy decision for the Mets to target a starting pitcher who is a pending free agent.

Gallen offers the most upside and Lugo is having another very good season for the Royals, but Kelly is arguably the most reliable of the bunch.

The question will be how much Arizona leans in as sellers.