Francisco Álvarez is looking to earn his stay after the Mets’ rise for the playoff-changing Braves series

The New York Mets promoted Francisco Álvarez to the majors on Thursday, just in time for their three-game set against the Atlanta Braves. The Mets head into Atlanta on Friday with a one-game lead over the Braves in the National League East. Whichever team wins the division gets a bye in the first round based on the second-best record in the NL. This would still have been a big streak, but it’s a critical streak, lasting less than a week in the regular season.

So Álvarez’s promotion is an interesting aspect of the weekend series. He will make his debut at a time when most prospects are either finishing their years or already enjoying the early days of their offseason. Why exactly did the Mets call him for the final days of the regular season — and what can he offer them? To get answers to these questions and more, let’s turn to a subhead format.

1. Why promote Álvarez now?

Álvarez’s promotion is odd only in that the Mets probably could (and should) have promoted him sooner. However, they are close to playing their most important series of the season so far and that deserves to have the best possible squad at their disposal.

The Mets take on Max Fried on Friday night. Fried is a left-hander who is likely to win the Cy Young Award this fall. Prior to Álvarez’s promotion, manager Buck Showalter would have had to choose between Darin Ruf (.413 OPS with the Mets) and Mark Vientos (.559 since promotion) for his right-handed DH. The Mets are banking on Álvarez being an instant upgrade over either of them.

The Mets won’t face another left-hander the rest of the way, but Álvarez could take key bats late in games or whenever the Braves (or New York’s eventual opponents, the Washington Nationals) try to play the matchup game against Daniel Vogelbach or another left-hander.

That seems like a lot to shoulder for a rookie – is Álvarez up to the task?

2. What is Álvarez’s game about?

Simply put, Álvarez is one of the best prospects in the game for a reason: He has tremendous raw power and he’s improved enough behind the plate to stay there.

Also, Álvarez is a 20-year-old looker who had split the season between double- and triple-A. In 112 contests, he had hit .260/.374/.511 with 27 home runs and 22 doubles. Those marks were impressive in their own right and fantastic considering his position and the fact that he was more than three years younger than your average opponent.

The Mets catcher combination of Tomás Nido and James McCann has struggled to produce on the record this season. Nido was by far the better of the two, and he’s hit just .242/.279/.319 (72 OPS+) with two homers in 302 plate appearances. Of course, given his inexperience with both the majors and the Mets’ pitching staff, Showalter might feel uncomfortable putting Álvarez behind the plate. Fair enough.

Álvarez can still offer value as a right-handed DH and pinch hit option. In addition to his totals listed above, he was particularly effective against left-handed pitchers. In fact, he hit .315/.424/.595 in more than 130 plate appearances against southpaws. It’s unlikely these grades will translate 100 percent to The Show, but to reiterate: Álvarez’s batting percentage against lefties (0.595) was almost equal to Nidos overall OPS (.598) and was well above McCann’s (.519).

3. Could Álvarez play in the postseason?

Absolutely. Álvarez is still qualified for the postseason despite not previously being in the active or 40-man roster.

Major League Baseball’s postseason eligibility rules dictate that a “A player who does not meet the stated postseason eligibility criteria may still be added to a team’s roster in the postseason by petition to the commissioner’s office,” provided the player was already on Aug. 31 in the organization and is “replacing someone who is on the injured list and has served the minimum time required for activation.”

Álvarez was in the organization on Aug. 31, and the Mets have several players on the injured list, including young infielder Brett Baty, who has been out since late August with a torn thumb ligament.

In other words, Álvarez’s cameo could double as an audition for a shot at post-season fame.