Dominic Smith didn’t think much of the pain in his foot when he first felt it a week ago. Everyone plays through something, he figured, citing the nature of competition and the inherent reality of a 162-game season, so he didn’t say much about it.

When he noticed things getting worse though, the left fielder brought it up to the Mets’ training staff Friday night. He thought it might require a foot massage to work out. He was told to get an MRI exam as a precaution.

That’s what brought Smith to his locker on Saturday afternoon, wearing a black T-shirt, headband and a walking boot on his left foot, as reporters pried for details. The Mets, less than an hour before that, announced Smith was going on the injured list with a stress reaction in his left foot. The injury was in his second metatarsal, near the joint, Smith said.

“I woke up this morning, I felt really good,” Smith said. “I’ve felt really good since the last couple days. I was excited about the last couple days and then to get in and heard the news, it just hurt. Hurt a lot. I’m very disappointed. Very sad. I’m gonna do everything I can to get back out there as soon as I can.”

Smith was placed on the 10-day IL, but an actual timetable is unclear until he gets a CT scan Monday. For his part, Smith said he felt pain in “every movement that I do athletically” though it wasn’t prohibitive.

It’s unclear what caused it — only that the injury was gradual. Smith doesn’t think he’ll be doing any baseball-related activity so long as the boot is on, though he did complete an upper-body workout before speaking with the media.

As for replacing him, the Mets will turn to a combination of J.D. Davis, Juan Lagares and Aaron Altherr, who the team called up from Triple-A Syracuse in correspondence with the move.

“I think we’ll look at it daily and see what we need,” manager Mickey Callaway said. “Do we need defense? Do we need offense? Does this guy match up well with this guy? And just try to make the best decision we possibly can.”

Smith had struggled at the plate over the past week, with just a .635 OPS in his past five games, but Callaway said it was unclear whether the injury was to blame. Still, finding a way to replace Smith’s production — the 24-year old has a .278/.352/.506 slash line — with the juggling act of Davis, Lagares and Altherr figures to be tough.

Davis, the best hitter of the three, has primarily played against lefties this season. It’s unclear whether that will change, but the 26-year-old figures to gain the most from the situation.

“Just like anything, going up through the minors, going through high school, going through college I faced righties all the time and I faced righties this season, I’ve been hitting pretty good off of them,” Davis told The Post. “I don’t think it’s a big adjustment. It’s just baseball, it is what it is.

“I know everyone said in the beginning that I was a lefty specialist, but I actually was having more success against righties most of the year until these last couple starts where I’ve been getting a lot more hits against lefties.”

Callaway sees Altherr as an option not just in left, but in all three outfield spots, citing strong defense and hitting in the minors. In 42 major league plate appearances this year, though, Altherr has all of two hits. Lagares, whose Gold Glove-caliber defense kept him around with the Mets for most of his career, has seen his advanced stats in the field drop off this year along with an abysmal .191 average at the plate.

Though the injury sounds minor in nature, Smith fielded a question about the worst-case scenario nonetheless, meeting it with something between caution and a hand-wave.

“I’m not worried. Whatever happens, happens,” Smith said. “Try to do the best I can to get back as quickly as I can, but like they say, we gotta be smart, because this is something that can linger on and you try to rush back, it can get worse.”