Jim McIsaac/Getty Images
Bay after striking out on July 19th
Before the 2009 season, Perez had a 55-60 career record with a 4.59 ERA.
The Mets saw this as good enough to reward him with a three-year, $36-million contract.
Over the next two seasons, Perez went 3-9 with a 6.81 ERA and 100 walks in 112.1 innings.
After refusing to go down to the minor leagues, the Mets sent Perez to the bullpen for the second half of the 2010 season and released him before this season.
They still owe him the remaining $12 million on his contract, though he's not even on the active roster.
Castillo was traded by the Twins to the Mets in the last year of his contract at the 2007 trade deadline.
He had a solid final two months, hitting .301 with one home run, 38 RBI and 19 stolen bases.
After the season was over, the Mets re-signed the free agent to a four-year, $25-million deal.
Over the next three seasons, Castillo averaged a .270 batting average and an OPS of .665, with his OBP never reaching higher than .387, not what you want from your leadoff/No. 2 hitter.
After setting a new single-season record for saves with 62 in 2008 with the Los Angels Angels of Anaheim, the Mets signed K-Rod to a three-year, $37-million deal.
In two-and-a-half seasons, Rodriguez went 9-10 with a 3.05 ERA, allowing 140 hits in 168 innings.
That's far from the 23-17 with a 2.35 ERA he posted over seven seasons with the Angels, allowing 305 hits in 451 innings, which would work out to 114 hits allowed using the 168 innings K-Rod pitched for the Mets as a scale.
The Mets' most recent disappointing free agent signing is left fielder Jason Bay.
Signed to a four-year, $66-million deal before the 2010 season, Bay has not come close to the production he had in either Pittsburgh or Boston.
In 719 games with the Pirates, Bay hit .281 with 139 home runs and 452 RBI, with an OPS of .890.
In 200 games with the Red Sox, Bay hit .274 with 45 home runs and 156 RBI, with an OPS of .915.
In 181 games with the Mets, Bay is hitting .255 with 15 home runs and 88 RBI.
That works it's way out, using the $24,625,000 Bay will make by the end of this season, to $1,641,667 per home run and $279,829 per RBI.
Not a great ratio there.
These are just the well-known ones. Here's a list of bad moves that flew under the radar: