MIAMI — This is a much different Jeurys Familia than last season.

Dave Eiland has the proof.

“He’s not sitting on that back leg anymore and that lift leg is coming right up,’’ Eiland told The Post Tuesday night before the Mets played the Marlins at Marlins Park. “He’s getting loaded and balanced over the rubber. He’s getting his hand out of his glove and his arm speed is really good. Getting the load on that back side gives that arm time to work.’’

That makes all the difference in the world.

Familia had gotten into some bad habits. His problem was that he was squatting down a bit on that back leg, collapsing and as a result, his arm was late.

The numbers also bear out the change. Familia leads the majors with five saves and has thrown seven scoreless innings this season.

“I’ve worked hard on trying to make the adjustments that [Eiland] wanted me to make,’’ Familia said.

The Mets’ bullpen had allowed two runs in the past 27 innings before Tuesday’s game, and a 0.67 ERA since April 1. The bullpen is ranked second in the majors with a 1.21 ERA. Only the Cubs (0.94 ERA) had better bullpen numbers entering Tuesday’s action.

Consider too that the Nationals went into the day with a 5.40 ERA to rank 26th. The Yankees’ highly rated bullpen was sitting with a 4.89 ERA, 24th best in the majors. You can see the secret to the Mets 8-1 start has been the pitching, specifically the bullpen.

Familia has posted those five saves over the first nine games, that is the most in team history and tied for the third-most in major league history. The only relievers with more saves in the first nine games were Armando Benitez in 2004 with the Marlins and Mike MacDougal in 2003 with Kansas City. Each had six.

Overall, the Mets staff has posted a 2.25 ERA, the best mark in the NL and second-best in the majors behind Houston’s 1.82 ERA.

Eiland and Mickey Callaway have done a terrific job so far guiding this staff.

For Familia, his pitches have better movement this season as he is near the league leaders in run and sink, according to internal Mets stats. His velocity is a tick down, but his ball is moving more and his velocity tends to be down a bit in the beginning of the year.

Familia is one of the most active pitchers in looking at video and every outing runs to the video room to check out his performance and to make the necessary adjustments.

Teammates marvel at what they have seen so far this season.

Veteran lefty reliever Jerry Blevins told The Post, “The biggest thing I see from him is not just how good his stuff is but what I see out of him is that he has advanced to that next level of understanding.

“He is starting to see things hitters are doing in the batter’s box. He is able to identify things, taking that next step. It’s a beautiful thing to have his stuff and also the baseball IQ is starting to take it to the next level. It’s a killer combo.’’

Familia has a tendency to walk the edge, making Mets fans nervous but if he can keep his mechanics sound and continue to understand the nuances of attacking the hitter that is a recipe for success.

Blevins has become so important to the bullpen in helping all the relievers.

“That’s the one thing I can bring to the table. I have to think out there, I have to notice stuff out there,’’ Blevins said, “but Jeurys is such a student of the game that I can’t take any credit for some of the stuff that he is doing. He is smart, he pays attention and the way he watches the game is different than it was a couple of years ago. It’s a fun thing to watch develop.’’

In Eiland, the Mets have a pitching coach who makes the necessary tweaks that are needed and Familia’s early success is a direct result of all that.