The New York Mets have failed to live up to expectations so far in the 2017 Major League Baseball season. They enter Tuesday with a record of 16-21, five games below .500, and certainly not competitive in the Nl East Division. The Mets are already eight games back of the Washington Nationals and it's only the midway point of May.

Given that more was expected of the Mets during the preseason, what exactly has gone wrong for them so far?

Injury part of the problem but not everything

The injury to Noah Sydergaard may seem like part of it, but really isn't the biggest issue with the Mets.

He has missed a few starts and, since he's such a valuable member of the team, that definitely hurts the Mets. It's fair to say that without him, New York isn't firing on all cylinders. However, the other pitchers on New York aren't nearly as effective as they need to be.

Jacob DeGrom hasn't been special this season so far. He has a record of just 2-1, his ERA is 4.07, and he has pitched enough innings this season to make his statistics meaningful. He leads the team in innings pitched with 48.2 innings of work thus far this season. He isn't really up to his personal standard yet, although DeGrom's performance on the mound certainly isn't terrible.

Two pitchers who are doing poorly are Matt Harvey and Ryan Gsellman.

They have both underachieved in major ways so far this season. Harvey is 2-3 with a 5.63 ERA on the year. Meanwhile Gsellman is much worse at 2-3 and at 7.07 for an ERA. Harvey and Gsellman are a big reason why the Mets, as a team, have given up 366 hits already. That ties them for the second-most hits yielded so far in the 2017 season.

Accordingly, the Mets certainly have a porous defense and their team ERA of 5.13 is actually the worst in all of Major League Baseball by a fair margin. The second-worst team in terms of pitching ERA is Atlanta, the Braves at 4.75 on the entire season.

Cespedes returning healthy could help

Slightly-above-average hitting has helped prevent the Mets from posting a below-.400 winning percentage.

Their team OPS is .736, good enough for 14th out of 30 Major League clubs. They aren't bad at drawing walks and that's helped with their on-base percentage.

Jay Bruce and Michael Conforto are the lineup mainstays that have helped New York the most. Without their contributions, the Mets might be among the very league worst this season.

Not only do the Mets need these players to stay healthy, but they also need Yoenis Cespedes to return to the lineup in full health. Currently, he has a hamstring problem and is on the short-term disabled list.

One positive change with the Mets lately involved Jose Reyes. He took a lot of at bats to start the season and had little to show for it in terms of productivity.

But TJ Rivera has earned the nod in his place and that might help the Mets offensively. That said, it's defense where they really need to improve. It would take a very special offense to get a winning record when your team ERA is 5.13.

The Major League Baseball season is long for American sports and with that comes forgiveness: you can start 16-21 and hope to get back into the picture over the long term. However, unless Washington comes down winning the division will be difficult for the Mets. This is a team that needs to make some changes to get back into the Wild Card picture.