Mets' decision to trade Miguel Castro for Joely Rodriguez was curious and could haunt them all season

When I first saw that the Mets had traded right-handed reliever Miguel Castro to the Yankees for left-handed reliever Joely Rodriguez, I thought I had to be reading it wrong.

Shortly after, I texted SNY contributor Joe DeMayo the following: "I despise the Castro trade."

At the time, it seemed curious that the Mets would trade a very good crossover reliever with elite stuff for a lefty specialist when the three-batter rule severely negatively impacts the value of lefty specialists -- especially ones (like Rodriguez) who are very bad against righties.

All offseason, I included Castro when listing the most important members of a Mets bullpen that also consisted of Edwin Diaz, Seth Lugo, and Trevor May. He was coming off an impressive 2021 season, and profiled as someone who could be part of the glue in the late innings.

That's why when the trade was made, I felt it was one the Mets would regret. And on Monday night in Philadelphia, as the shorthanded Mets were trying to scratch out a win over the Phillies, it was Rodriguez whose struggles helped do them in.

To be clear, it's hard to blame Rodriguez for what happened. After all, he is not effective against right-handers and should never be asked to face elite right-handed bats in a close and late situation.

But Rodriguez, who had been tasked with pitching to the left-handed Kyle Schwarber in an inning where the lefty-swinging Bryce Harper was also due up (Rodriguez got both of them out), was in there against right-hander J.T. Realmuto with the Mets leading, 4-1. And it came as no surprise when Rodriguez grooved a middle-middle pitch to Realmuto, who crushed it over the left field wall for a two-run homer.

You can blame Buck Showalter for having Rodriguez in the game, but that wouldn't be entirely fair. Not when the front office removed Castro from the bullpen and replaced him with Rodriguez, and especially not when the Mets were still without Edwin Diaz (who was on the bereavement list) and had just lost Trevor May to injury.

So, why exactly did the Mets trade Castro for Rodriguez?

Let's take a look at the crossover numbers from 2021...

In 140 plate appearances against right-handers last season, Rodriguez allowed a triple slash of .339/.380/.446.

In 147 plate appearances against left-handers last season, Castro allowed a triple slash of .198/.313/.270. 

Castro's OPS allowed against lefties (.583) was better than it was against righties (.655), though both marks were elite. For comparison, Rodriguez's OPS allowed against lefties last season was .559.

Let's take a look at the overall numbers from 2021...

Rodriguez had a 4.66 ERA and 1.53 WHIP with 47 strikeouts in 46.1 innings.

Castro had a 3.45 ERA and 1.29 WHIP with 77 strikeouts in 70.1 innings.

Maybe the Mets know something about Castro that made them think twice about the likelihood of him repeating his 2021 success in 2022. Maybe the Mets think they can turn Rodriguez into a pitcher who can have success against right-handers. But even if they do, the Castro for Rodriguez swap made little sense.

At the moment, the trade looks like a serious mistake. And if May has to miss time, the absence of Castro will likely hurt even more.

The Mets could have avoided trading one of their better relievers for a lefty specialist had they simply re-signed Aaron Loup (who was dominant against lefties and righties last season) or signed another impact left-hander on the free agent market. They didn't, instead bringing in Chasen Shreve on a minor league deal.

After passing on the top lefty relievers in free agency, the Mets did not have to force a trade for a lefty specialist -- especially when they had a pitcher in Castro who was very good against both righties and lefties in 2021 (and had several other relievers, including Drew Smith and Lugo), who are also effective against lefties.

To get back to Rodriguez, it needs to be noted that his ineffectiveness against right-handers last season was so glaring that the Yanks viewed him as a lefty specialist when acquiring him from the Texas Rangers -- going out of their way to avoid using him against right-handed hitters.

The above led to the Yankees often using Rodriguez for just 1/3 of an inning or 2/3 of an inning, meaning he was often called upon in the middle of an inning to get one or two outs and then pulled -- a way to get around the three-batter rule, which does not carry over from inning to inning.

That the Mets traded Castro for Rodriguez was bizarre. And the way they used Rodriguez on Monday night against the Phillies set him and the team up for failure.

Going forward, the Mets will have to limit Rodriguez's exposure against righties or figure out a way to help him succeed against righties. But either way, the Castro for Rodriguez trade looks worse today than it did when it was made -- when it already looked pretty bad.