CHICAGO — Dedniel Nunez’s right forearm tightness was enough to place him on the injured list, but a day later, there was some level of optimism the right-hander’s season might not be over.

The rookie reliever returned to New York following the completion of the series in Arizona on Thursday.

Initially, the expectation was Nunez would receive an MRI exam on his forearm, but manager Carlos Mendoza said Friday, before his team’s 5-1 win over the White Sox, there was still discussion whether that step would be needed.

“Now we’re kind of going back and forth whether he needs an MRI or not,” Mendoza said before the game. “Maybe we’ll wait a couple of days and see how he feels and get treatment after that.”

Mendoza said the team’s trainers believe the ulnar collateral ligament in Nunez’s forearm hasn’t been compromised and is “in a good spot.” Nunez will rest for a few days, then be evaluated.

“It could be a quick ramp up if everything comes out good,” Mendoza said.

Nunez returned from the IL last weekend (he was sidelined with forearm tightness) and after his first appearance had discomfort, leaving him unavailable to pitch in the series against the Diamondbacks.

Nunez has been among the best Mets relievers this season, with a 2.31 ERA in 25 appearances.

Christian Scott has begun throwing from a mound (only fastballs) and is expected to soon add his breaking pitches into the mix.

The right-hander remains a possibility to rejoin the Mets in some capacity as he rehabs from a sprained ulnar collateral ligament in his right elbow.

Kodai Senga has moved forward in his rehab and has started long tossing, according to Mendoza.

The Japanese right-hander, who is recovering from a calf strain, could be a possibility to contribute if the Mets reach the postseason.

Jett Williams was reinstated from the injured list at Double-A Binghamton after rehabbing from a TFCC debridement procedure on his right wrist.

Williams, last season’s organization Player of the Year, last played in April.

The 20-year-old Williams, who is primarily an infielder, was in spring training with the Mets this year.

Mets pitchers lead the major leagues with 16 pickoffs.

The total is the team’s highest since 1987, when Mets pitchers had 20 pickoffs.

With the loss, the White Sox will need a 12-14 finish to avoid tying the 1962 Mets for the most losses (120) in a season.

The White Sox were within two losses of tying the franchise record for futility. The 1970 White Sox went 56-106.