Francisco Lindor’s fourth straight day removed from the Mets lineup was to be spent exercising indoors Thursday and devoid of the kind of on-field baseball activity that might indicate his return was imminent. 

The Mets shortstop, bothered by a sore lower back, has been on a 2-5 day timetable for a return since Monday, when he received a clean MRI result for his back.

Manager Carlos Mendoza wasn’t about to revise that timetable before the Mets opened a four-game series against the Phillies at Citi Field, but also didn’t sound upbeat about the possibility of Lindor’s return occurring within the original window. 

“He is slowly getting better,” Mendoza said. “We are still calling it day-by-day. Hopefully he turns a corner to a point where we get close to making a decision for him whether he’s a player or not.” 

Mendoza added “there is a chance” Lindor will play this weekend against the Phillies. 

The Mets didn’t much miss their star shortstop over three games against Washington (all victories) in which rookie Luisangel Acuna, starting in Lindor’s spot, emerged with two homers.

Jose Iglesias is batting leadoff in Lindor’s absence, and the veteran infielder has responded: He went 6-for-12 (.500) in the sweep of Washington. 

But the NL East-leading Phillies will likely present a stiffer challenge for the Mets, who began the day tied with Arizona for the NL’s second wild card and 1 ½ games ahead of Atlanta for the third spot.

The Mets and Braves still have a potentially huge three-game series next week in Atlanta. 

The standings, according to Mendoza, have no bearing on when Lindor will return to the lineup. 

“When he is ready to go he’ll play, regardless of where we are at on the schedule and in the standings,” Mendoza said. “If he is a player for us he will play, but if he can’t go, regardless of the situation, we’re not going to put him at risk, so whenever he tells us. This is a guy who has played through pain, he’s done it a lot of times. If he gives a green light, like, ‘I can go without compromising some other body parts,’ then we’ll put him in.” 

Lindor had been playing through back discomfort, but aggravated his condition in Philadelphia last Friday, when he overran second base on a double and was later removed from the game.

Lindor missed his first game of the season on Saturday and then attempted to play a day later, but was removed after only 1 ½ innings because of back discomfort. 

Lindor entered Friday as the NL leader in fWAR at 7.4, giving him a case for MVP. Shohei Ohtani was next on the list at 7.0. 

If it weren’t so late in the season, the Mets would be nearing a point where an injured list stint might be considered for Lindor.

But the Mets aren’t about to chart that course and eliminate him from potentially playing in the Braves series next week.

And the expanded September roster allows the Mets to absorb Lindor’s absence without leaving the bench short.

Eddy Alvarez, who arrived in a trade during the last Mets road trip, provides the team with an extra infielder. 

“It could be one of those where [Lindor] shows up and turns the corner,” Mendoza said. “You never know with these back issues.”