I believe Seth Lugo is the most reliable reliever in the Mets bullpen. You can put him in any situation and he will find a way to get outs. He missed the first two months of the season but has posted a 2.65 ERA in 16 appearances. Will be a huge piece of the second half for the Mets.
If this guy can ever stay healthy he will end up being a big piece in the Mets bullpen in the future. This season he has excelled in low-medium leverage situations, posting a 2.92 ERA in 19 appearances. His ability to go more than three outs has been a huge help as well. Walks are a bit of an issue though, as he has walked 4.4 batters per nine.
Megill clearly was not fully ready to pitch in the majors but has done better than I expected as someone who was forced into the rotation due to all of the injuries. He has struck out 26 batters in his four starts, along with a 3.50 ERA. The only downside has been his inability to pitch deep into games but he has kept the Mets in games which is really all you can ask for.
I thought Familia was pretty much a lost cause but he has actually been a pretty big piece in this Mets bullpen. Walks are high, but they always will be high. His 3.77 FIP is over a run better than his FIP’s in the other two seasons he has been a Met since he re-signed.