In the days leading up to the MLB trade deadline, relief pitchers were in high demand. The St. Louis Cardinals were among the most active sellers, dealing multiple arms – including one of the league's best, Ryan Helsley.
The two-time All-Star ended up getting moved to the Mets as a rental player with an expiring contract. New York was able to pair Helsley with Edwin Diaz, hoping that the two closers would help upgrade them for the postseason.
However, Helsley wasn't the Mets' first choice from a large list of relief arms that were available in trade talks. Athletics closer Mason Miller was.
Miller would end up getting moved to the Padres because of the talent that San Diego was willing to part with to trade for Miller.
The Athletic's Ken Rosenthal reported on the situation, saying that the A's were more interested in MLB's No. 3 prospect Leo De Vries, ultimately committing to a deal with San Diego.
"Athletics GM David Forst told reporters, 'When the Padres suggested they were open to including Leo (De Vries), that’s kind of when this got serious.' Preller said it was actually the A’s who proposed a deal including De Vries a few days before the deadline, telling the Padres, 'Hey, if this is something you want to do, this is the structure,'" Rosenthal wrote.
After these conversations took place, the Mets had to pivot, ultimately coming to the conclusion that Helsley would be the next best option. Even though the Cardinals' closer's contract would be expiring at the end of the season, he would upgrade New York's bullpen with the intent to use him for a strong push come October.