Glass-half-full Mets fans -- and they know who they are -- look at the second half of the 2019 season and actually feel good about their team’s chances going into 2020, even looking up at the Braves and the Nationals in the National League East. The Mets were 40-50 in the first half last season and then went 46-26 after the All-Star break, second in the National League to the Dodgers. The Mets were still in the Wild Card conversation into the last week of the regular season. They ended up with Jacob deGrom winning his second consecutive Cy Young Award and Pete Alonso hitting 53 home runs and winning Rookie of the Year. It was a much better season than anybody thought they’d have on July 1.

Now second-year general manager Brodie Van Wagenen and his rookie manager, Carlos Beltrán, have to figure out a way to go get the Braves and the Nationals and stay ahead of the Phillies. The Braves aren’t going anywhere. The Nationals are the reigning champions. Optimistic Phillies fans -- and they know who they are -- have to figure things are going to get better under Joe Girardi, who should finally help them be more than a .500 team.

The challenge for the Mets, then, is moving up this season, and not down. Everybody has questions at this time of year, especially with the Winter Meetings about to begin. Here are five for the Mets:

1) Will Yoenis Céspedes ever play for them again?

Céspedes was the star of the run the Mets made all the way to the World Series in 2015. He hasn’t played since 2018. The last time he made news was in May, when he underwent ankle surgery for what was described as a “violent fall” at his Florida ranch. Mets fans sort of saw it as another fall from grace.

Céspedes is entering the final season of the four-year, $110 million contract he signed before the 2017 season. The Mets have no idea if he will play in 2020. Waiting for Céspedes has become the baseball equivalent of waiting for Godot to come play the outfield at Citi Field.

Put him in the Mets batting order with Alonso and Michael Conforto and Jeff McNeil and Robinson Canó and J.D. Davis, and you can see the possibilities for the Mets. Or Céspedes is gone for good. And the end of his contract turns out to be as big of a disappointment for the Mets as David Wright’s ultimately became.

2) What can they expect from Edwin Díaz?

The Mets got Díaz, coming off a 57-save season, along with Canó from the Mariners last winter. And Díaz actually seemed fine over the first couple of months of the season. Until he wasn’t. Until he began to turn one late-game situation after another into one of those Citi Field fireworks displays.

He ended up with a 5.59 ERA and a 2-7 record. He had seven blown saves that felt like 70 to Mets fans. He gave up an amazing 15 home runs in 58 innings.

Now there are rumors that the Mets might actually be willing to part with prospects to get Josh Hader out of Milwaukee, because the guy for whom they gave up two first-round Draft picks -- Jarred Kelenic (No. 6) and Justin Dunn (No. 19) -- last winter drastically underperformed.

Díaz won’t turn 26 until March. He did strike out 99 guys last season. Problem is, the Mets don’t know whether last year was an aberration, or if Díaz is another baseball star from out of town who can’t make it work in New York.

3) Who plays center field?

There were a lot of issues with the 2019 Mets, especially over the first half of the season. But other than Díaz, the biggest one might have been defense. The Mets were the worst fielding team in the National League with -93 Defensive Runs Saved, and the Orioles were the only team below them in all of MLB.

Juan Lagares has always been able to catch it in center. He hit .213 last season and is a free agent. Brandon Nimmo had his moments after getting healthy again, and he is an OBP machine, but he’s probably better suited to a corner outfield spot.

There have been rumors of the Mets looking to trade for Pittsburgh’s Starling Marte, which would make sense, because they don’t currently have a true center fielder.

4) How much are they willing to spend?

As of now, the Mets’ projected 2020 payroll for the purposes of the Competitive Balance Tax is in the $185-190 million range (per Cot’s Baseball Contracts). The CBT threshold is $208 million for 2020, which means that as a “first-time offender,” they would be taxed at 20% on every dollar spent above $208 million.

David Wright is still on the books, for the last time, and his salary still counts as $17.25 million toward the CBT. (The CBT uses the average annual value of the contract, as opposed to the salary in that specific season.)

Céspedes is also still on the books for 2020. So is Jed Lowrie. And Wilson Ramos. And Marcus Stroman. And then they are all free agents. Which means that the Mets should be able to get back under the CBT threshold for 2021, even if they go over this year. So would they be willing to pay the CBT this year for the right player? Conceivably, yes. Will they actually do it? Another matter entirely.

5) Who is the fifth starter?

Your guess is as good as Van Wagenen’s, or Beltrán’s, with Zack Wheeler almost certainly leaving as a free agent. They have deGrom, you bet, the best in class. They have Noah Syndergaard. And Marcus Stroman. And Steven Matz. Are they really willing to risk moving Seth Lugo out of the bullpen -- as has been rumored -- and lose their best relief weapon in what could be a risky conversion plan? Or does Lugo stay in the bullpen and they fill the fifth spot from the outside? This isn’t the most pressing question facing the team, but it’s still a big one.

The Mets can definitely make a move this season. Maybe the biggest question of all is this one: In which direction?