Mets leftfielder Brandon Nimmo rounds third base on his solo...

Mets leftfielder Brandon Nimmo rounds third base on his solo home run against the Washington Nationals on Sept. 24, 2017. Credit: Kathleen Malone-Van Dyke

PORT ST. LUCIE, Fla. — Players always check the lineup card early in the morning in spring training. They generally know if they’re in the lineup, but batting orders can be fluid, especially when there aren’t a lot of regulars playing on a particular day.

On the 2018 Mets, particular attention was paid during spring training to the first line of the lineup card. Rookie manager Mickey Callaway experimented with different leadoff men, some of them names you wouldn’t expect to see in the first spot in the order.

The Mets will go into the season without a “traditional” leadoff batter. Brandon Nimmo should get the first crack at the spot — if he’s in the Opening Day lineup — but he’s likely to not even be a regular when Michael Conforto returns from shoulder surgery around the first of May.

Conforto could end up getting the most at-bats at the leadoff position this season. Or the Mets could decide they need his power production in the middle of the order, in which case the No. 1 batter could be Asdrubal Cabrera. Or it could be Jose Reyes on the days he starts.

Reyes was the Mets’ first batter on Opening Day last season. He has the most plate appearances in the leadoff spot in team history (4,876), according to the Elias Sports Bureau. Mookie Wilson is next with 3,147, followed by Bud Harrelson with 2,321.

But Reyes isn’t a regular anymore. So it seems as if checking the lineup card — especially that first line — will be a daily activity for the Mets during the regular season as well.

And that’s sort of the way Sandy Alderson designed it.

As the general manager put together the 2018 Mets, he did not seek out a traditional leadoff man. “I wouldn’t say that it’s not important, but personally I tend to focus on one through nine and that the most important thing is not a particular slot in the lineup, but the entirety of the eight or nine men that are playing,” Alderson said. “And the definition of a traditional leadoff man has changed over the years, too.”

ON BASE IS (RIC)KEY

Alderson’s preferred leadoff man is Rickey Henderson, who is only the best one in baseball history. Alderson inherited the future Hall of Famer when he took over as the Oakland A’s general manager in 1983.

“When I was in Oakland, we had probably the perfect leadoff man, Rickey Henderson,” Alderson said. “He had it all. He had power as well. When I got involved in baseball, I was always grounded in, quote, ‘analytics’ because I didn’t really have any experience in the game. So I wasn’t limited by that conventional wisdom. I didn’t have any conventional wisdom. And I didn’t even have to think about it for a while because we had Rickey Henderson. Early on, from my career in baseball, I’ve always been on-base-oriented.”

Henderson is baseball’s all-time leader in stolen bases, but it was his on-base percentage (.401 career, a high of .439 in 1990) that Alderson fell in love with. That’s what he’s looking for in a leadoff batter — or any batter, really.

“It starts with on-base percentage,” Alderson said of his criteria for a leadoff man. “Then it goes to base-stealing ability. Then it goes to ability to handle the bat like a more traditional No. 2 guy. But the first priority is on-base percentage.”

STEAL OR STAY PUT?

That’s where Nimmo comes in, especially until Conforto’s season begins. Nimmo, who was Alderson’s first first-round pick as Mets general manager in 2011, has thrust himself into the conversation because of his .379 on-base percentage in 2017.

That Nimmo stole only two bases is considered irrelevant. The game has changed to the point that teams want players to attempt stolen bases only if they can make it at a high percentage. Otherwise, teams prefer baserunners to stay put and wait for a home run.

In 2017, the Mets were last in the National League in stolen bases with 58. Reyes had 24 of them.

“Nowadays, there’s no more, like, you have to have speed and steal bases,” Reyes said. “It’s changed. Some of the teams want a power hitter for leadoff. Look at Conforto. You look at Houston, they’ve got [World Series MVP George] Springer. It’s crazy. Nowadays they want a guy who takes a lot of pitches like Nimmo. I’ve talked to Nimmo about stealing bases a few times. He’s got speed.”

Nimmo’s career high in stolen bases is 14 in the minors in 2014. With Yoenis Cespedes slated to bat second, the Mets don’t want Nimmo attempting to steal too often. They’d rather see Cespedes hit a two-run homer.

“It’s interesting,” Alderson said. “If you look at who’s hit leadoff for the Mets over the years, I’m not sure you could say that anybody has been ideal. Even when Jose Reyes was the leadoff man, he wasn’t a particularly high on-base-percentage guy.”

LEADING MEN

Let’s look at who’s hit leadoff for the Mets over the years by focusing on their five World Series teams:

In 1969, Tommie Agee hit first in all five World Series games. In 1973, Wayne Garrett hit first in all seven World Series games. In 1986, it was Wilson in Games 1 and 7 and Lenny Dykstra in the middle five. In 2000, Timo Perez hit first until Game 5, when Bobby Valentine went with Benny Agbayani. In 2015, Terry Collins wrote Curtis Granderson’s name in the leadoff spot for all five games against the Royals.

Granderson is a low-average power hitter who walks a lot. You may not think of him as a leadoff man, but his managers have. He has hit in the leadoff spot 4,024 times, which by far is the most plate appearances in one spot in his career (second is next at 1,292).

As for Conforto, he has it all for a leadoff man — except for the stolen bases. He also has it all for a No. 2, 3 or 4 hitter, which is why the Mets will always face a (good-to-have) decision about where to hit Conforto.

“Michael Conforto gets on base at a .375 clip,” Alderson said. “That’s pretty good for a leadoff guy. Really good. The downside is that with the power he has, you’d like to bat him a little lower in the lineup. But maybe with a less conventional leadoff man, it causes one to build the bottom of the lineup a little more. Change the pitcher from hitting ninth to hitting eighth. There are a variety of other things you can do to mitigate the impact of a non-traditional leadoff man. But for us, especially with the game built so much around power, the key is to get on base. A guy like Brandon Nimmo, if he were to play, would be excellent.”

Said Conforto: “I didn’t have much experience there, so I didn’t really know what to expect. But I really liked it. I liked that usually every night I was getting five at-bats. I like being the first hitter of the game. I think you get a pretty good idea of what’s coming at you. To get to start the game off aggressively and kind of set the tone a little bit, I really enjoyed it.

“I didn’t necessarily feel like, ‘Oh, I’m a leadoff guy, so I have to fit this profile. I have to be a guy who gets on base, steals bases, creates things that way.’ I’m not trying to slap the ball anywhere or anything like that. You go first-pitch home run, it almost feels like it’s unfair. Everybody knows what’s coming there. I like that aggressive approach being the first hitter of the game. I also like leading off the game with a walk. Everybody feels great when the leadoff guy gets the game going in the right direction.”

Except for the stolen bases, Nimmo fits the mold of a traditional leadoff guy because he lacks big power. If he doesn’t bat first, he most likely will hit at the bottom of the order — perhaps ninth, behind the pitcher.

“I got my resume in for whatever they want,” Nimmo said. “Anywhere I can play on an everyday basis, I’m all for it. Wherever that is, doesn’t matter to me. I’m all-in.

“Last August and September was big for me. Just the fact I got to play on more of an everyday basis. They got to see that I could produce at the big-league level.”

CREATIVE CALLAWAY?

So who’s it going to be? Probably Nimmo for openers and then maybe Conforto, for the most part. Alderson wouldn’t handicap the options, because, as he said, “I think Mickey is trying to be creative and I’d hate to limit his creativity.”

New Mets manager Mickey Callaway’s Opening Day lineup will be the first he’s ever filled out for a professional baseball game that counts. The former Indians pitching coach will take input from Alderson and his coaches, but Callaway eventually will have to make the final call. It’s not something he’s taking lightly, but that doesn’t mean he won’t change it for subsequent games. Remember, if at first you don’t succeed . . .

“I think it’s very important, especially depending on where you’re going to hit your other best hitters,” Callaway said. “I think it’s one of the most valuable spots in the lineup.”

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