While some of the aforementioned closers have helped the Mets win championships, none have been around and done as much for the team within a 15-year span like John Franco did. Thus, he should be considered the greatest relief pitcher the Mets have ever had.
Coming to New York from the Reds in a trade for Randy Myers before the 1990 season, Franco was already an established closer and picked up where Myers left off.
Arguably the best overall Met throughout the 1990s, Franco began turning in one successful season after another and racked up many saves, averaging 26.8 saves per year through the decade.
Franco's first great year was 1990, when he made his only All-Star appearance and saved 33 games, setting a new Mets record while posting a 5-3 record and a 2.53 ERA.
In 1991, Franco went 5-9 with a 2.93 ERA and 30 saves. He then went 6-2 with a 1.64 ERA and 15 saves in 1992 and 4-3 with a 5.20 ERA and 10 saves in 1993, but missed a good chunk of each of those seasons due to elbow injuries.
In 1994, Franco started to enter his prime and went 1-4 with a 2.70 ERA and 30 saves. He followed this up with a 5-3 record, 2.44 ERA and 29 saves in 1995.
In 1996, Franco was 4-3 with a 1.83 ERA and 28 saves. He got his 300th career save in late April of that year and a few weeks later, on "John Franco Day," Franco himself got ejected after participating in a bench-clearing brawl, along with eight other players.
In perhaps his best season as a Met, 1997, Franco went 5-3 with a 2.55 ERA and 36 saves, which broke his own Mets record.
In 1998, Franco was 0-8 with a 3.62 ERA and 38 saves, which broke his own team and personal record.
Throughout the 1990s, Franco was dominant against the National League. However, compared to other premier closers at the time, Franco was rather underrated, and his overall numbers usually went unnoticed. As a result, he was snubbed from the All-Star game more than he should have been.
Franco was always a popular player during his time with the Mets. He was also very active with the MLB Players' Union, and he spent some time as the Mets representative. In 1998, after Mike Piazza was acquired, Franco voluntarily gave up his No. 31 and switched to 45 in honor of Tug McGraw so Piazza could have his usual number.
After the arrival of Armando Benitez, Franco converted to a set-up man (and eventually, team captain) for the rest of his Mets years. In 1999, Franco was 0-2 with a 2.88 ERA and 19 saves. He missed part of the season due to injuries, which led to Benitez becoming the new closer. He finally made it to the postseason that year and had a 1.69 ERA in the playoffs.
In 2000, Franco was 5-4 with a 3.40 ERA and four saves. He pitched well in the NLDS that year but struggled in the NLCS, as illustrated by his 6.75 ERA in that series. In the World Series, he was the winning pitcher in the only game the Mets won.
In 2001, Franco went 6-2 with a 4.05 ERA and two saves. The 9/11 attacks hit the Brooklyn native hard, and he was very active in the relief efforts.
After missing all of 2002 with injuries, Franco came back in 2003 and went 0-3 with a 2.62 ERA and the last two saves of his Mets career.
In his last season in New York in 2004, Franco was 2-7 with a 5.28 ERA. By then, the Mets organization was chaotic and the late 1990s to early 2000s core slowly got broken up.
Franco spent a year in Houston in 2005 before subsequently retiring and becoming the team ambassador he is today.
Many non-Mets fans would probably not know Franco is fourth all time in saves and first among left-handed pitchers. Only Trevor Hoffman, Mariano Rivera and Lee Smith have more saves at the moment.
Franco may not have had the noticeable dominance that other closers of his time had nor the postseason experiences that defined other Mets closers like McGraw and Orosco, but Franco nonetheless is one of baseball's greatest closers and his 424 career saves speaks for itself.
Franco was on the Baseball Hall of Fame ballot for the first time in 2011 but because he received less than 5 percent of the vote, he will unfortunately never appear on a regular Hall of Fame ballot ever again—unless the Veterans Committee decides to give Franco a second chance down the road.
Franco may not have won a championship with the Mets, but his contributions to the franchise have been very significant, and he should be considered the greatest closer the Mets have ever had.