David Wright calls it “my back thing.”

It’s one of the few major issues in spring training for the defending National League champions. How many games will David Wright be able to play this season? The captain only gave a chuckle when he was asked that question earlier this week.

Wright’s spinal stenosis is the most day-to-day situation on the Mets. He won’t play in spring-training games until next week at the earliest. He said he doesn’t know each day how much work he’ll be able do to until he rolls out of bed.

“It’s how I feel in the morning,” Wright said. “I feel like when I wake up — I’ve probably said this a million times — when I wake up, you can tell right away what kind of day it’s going to be. If it’s one of those bad days, you’ve got no shot at really doing anything productive.

“Normally it’s somewhere in between the two and with the hour, hour and a half routine I do before I take the field, it usually kind of helps me turn the dial a little bit more towards, ‘OK, we can manage this.’ ”

Wright played in 38 regular-season games last season and hit .289 with five home runs and 17 RBIs. He started all 14 postseason games and hit .185 with one home run and seven RBIs. Wright is signed through 2020 and has $87 million left on his contract (including this season).

Wright once played through a broken back, so you know if there’s any way he can be out there, he will. But at age 33 his “back thing” is not going to go away. It’s part of who he is now.

“I don’t really look at it like ‘poor me,’ ” Wright said. “I got eight, nine, 10 years of relatively good health. So the back thing is just kind of a combination of some bad luck, some specific plays over the course of 13 years. It’s a challenge. But what am I going to do? Whine about it? Cry about it? Or you can just do what it takes to play the game.”

Wilmer Flores and Ruben Tejada started at third base in the Mets’ two games Monday. Flores might be Wright’s main backup when the regular season opens April 3 in Kansas City.

Flores made a diving stop for a forceout in the first inning and a running catch on a short foul pop-up in the sixth in the Mets’ 7-3 victory over the Tigers.

“With what’s going on with David, we’ve got to get him comfortable over there,” manager Terry Collins said of Flores, who went 0-for-3.

Tejada handled his only chance and went 1-for-3 in the Mets’ 9-4 loss to the Cardinals in Jupiter.

Collins said Wright will play in only “10 or 12” games in spring training. Before that’s even considered, Wright said he has to prove he can run the bases.

“The number of games means very little,” Wright said. “If I need at-bats, I can always hop on to the minor-league side and get four, five at-bats in 15 minutes … I feel like I’m pretty close. I think part of it is being a little cautious. Part of it is with my back thing that I don’t think they see the need to throw me out there right now.”

Still, Wright said he has no doubt he’ll be ready for the season.

“I think you’re still talking about a long ways away,” he said. “I think that this could be beneficial to me because I’m getting really good work in. The last couple days, I’ve gotten some really good sessions in with as far as my fielding goes. There were some things that I felt I need to work on mechanically fielding and I wouldn’t be able to do that along with getting ready for a game. I’m looking at it in the positive side where I’m a little late getting into games, but I’m getting some work in that I normally wouldn’t be able to get in.”