So when the Mets acquired him, alongside fellow young pitchers Gerson Bautista and Stephen Nogosek for the too-short-lived Addison Reed in 2017, it seemed like he had a bright future. He had a 1.80 ERA in 9 relief appearances for New York's Triple-A club. They called him up that year for his first big league trial; he was only 22 years old.

Yet October 1, 2017 marked his final big league appearance. He wasn't bad in his 9 outings -- he had a 4.05 ERA and averaged nearly a strikeout per inning -- but that one brief stint in the majors is all he's seen of The Show.

It just seems like he forgot how to pitch. His ERAs in the succeeding campaigns, all spent in the minor and independent leagues, were 9.72, 5.01, 8.10 and 7.04, respectively. He last pitched professionally in 2021, though he is still just 27 years old, so he might not be done yet.

Callahan was one of a slew of young hurlers the Mets received via trade in 2017. In addition to Bautista and Nogosek, they acquired Ryder Ryan, Eric Hanhold, Jacob Rhame and Drew Smith. Only Smith has done anything with the club.

As a Mets fan, I have an "I'll believe it when I see it" attitude toward young acquisitions. Only when they actually do well will I believe they have the potential to do well.

Unfortunately, I never got to believe it with Callahan.