Despite being unable to land Grandal, the Mets signed Wilson Ramos for $19 million over two years in mid-December.
Grandal remains unsigned, with Castillo adding a return to Los Angeles is unlikely unless the 30-year-old is willing to accept a shorter contract.
The catcher position was clearly a priority for the Mets this offseason. Mike Puma of the New York Post reported in early December that talks had taken place over a deal involving Noah Syndergaard and Miami Marlins catcher J.T. Realmuto.
While it never came to fruition, the speculation around the deal showed how much New York's front office wanted another backstop alongside Travis d'Arnaud, who missed most of last year after undergoing Tommy John surgery.
Grandal's decision to decline a $60 million offer from the Mets is surprising, though the full details of the deal are unknown. It could've included performance-based incentives or a club option in the final year or two.
Assuming it was a standard four-year contract, Grandal's $15 million average salary would've been the fourth-highest among catchers, per Spotrac.
Grandal is coming off a career year, though, and his value is unlikely to ever be higher were he to hit the open market again. He batted .241 with 24 home runs, 68 RBI and a .466 slugging percentage in 2018. His 3.6 WAR were second-most at his position, per FanGraphs.
With a few of this year's top free agents still available, Grandal is likely waiting for a bigger deal than he would've received from the Mets.