PORT ST. LUCIE — David Peterson figured it was just normal aches and pains.

But after pitching through discomfort for much of last season and finding little relief afterward, the Mets left-hander got evaluated and was told he had a torn labrum in his left hip.

“Most of last year, it was just kind of one of those on-and-off things,” Peterson said Wednesday at Clover Park. “It just kind of felt like my body was beat up and then we decided to see what was going on and take a look. That is kind of when we found out everything that is going on.”

Peterson underwent November surgery that will keep him out at least the first month or two of the season.

He has begun playing catch and working out, his mind at rest that the surgery has worked.

Last season was a roller coaster for Peterson, who pitched to a 5.03 ERA in 27 appearances for the club.

Ineffective early in the season, he was optioned to Triple-A Syracuse.

After the All-Star break he provided the Mets with a needed arm in the rotation and bullpen and pitched to a respectable 3.65 ERA.

Once healthy, Peterson will join the rotation depth that as camp begins includes Tylor Megill, Joey Lucchesi and Jose Butto.

“Depth pieces, especially at starter, never hurts,” Peterson said. “I think they have that in mind and I am looking forward to getting as healthy as possible as soon as I can and be able to go out there and help this team win.”

The Mets officially announced Shintaro Fujinami’s signing and placed Ronny Mauricio on the 60-day injured list to create space for the right-hander on the 40-man roster.

Fujinami, who received a one-year contract worth $3.35 million, is awaiting a visa and will work out independent of team activities at Clover Park until the issue is resolved.

Last season Fujinami — whose primary weapon is a fastball that touches 100 mph — pitched for the A’s and Orioles, moving from the starting rotation to relief. The Mets will use him as a reliever. Overall, he pitched to a 7.18 ERA.

Kodai Senga and Fujinami were teammates for Japan’s WBC team in 2017. Senga said stability should help Fujinami this season.

“It was obviously a very dramatic season for him, beginning as a starting pitcher with Oakland and then moving to the East Coast and becoming a relief pitcher, changing midseason,” Senga said through his interpreter. “I think he will adapt quickly to our team as well and being a Japanese player on the same team hopefully we can chat about things and take it to a higher level.”