NEW YORK -- Of all the slumping Mets -- and there have been many in this early part of the season -- Francisco Lindor has stood out because of who he is. Lindor was the headlining piece of the Mets’ offseason makeover. He signed a $341 million contract extension on the eve of Opening Day, and endeared himself to fans with his flash, his smile, his potential and his pizzazz.

All of that has been on display throughout April. His offense simply hasn’t, prompting folks to take notice. As Lindor grounded out softly in his final plate appearance of Tuesday’s 2-1 loss to the Red Sox, he heard a smattering of boos at Citi Field. Lindor has hardly been the only culprit for a team that ranks last in MLB in runs per game (3.0). But he has been the most noticeable slumping player in the Mets’ lineup, which on this night made him the subject of fans’ ire.

“Watching him in camp, how good he swung the bat in camp, I just feel that he’s one swing away, one at-bat away,” manager Luis Rojas said. “I keep saying it, because he’s got good body control, he’s got a good feel of what he’s doing there. Right now, his swing is just a little off.”

Rojas noted that Lindor seems to be trying to pull nearly everything pitchers give him, which was certainly true against Red Sox starter Garrett Richards:

• In his first at-bat, Lindor swung at a 94-mph fastball off the outer edge of the strike zone. He pulled it directly into a defensive overshift.

• In his second at-bat, Lindor received a curveball even further off the plate. He appeared to try to go with that one, bouncing it weakly to third base.

• In his third trip to the plate, Lindor lunged at a Richards slider low and away, yanking it up the first-base line for a 52-mph infield hit.

• In his final at-bat, Lindor again tried to pull a ball off the outer edge of the strike zone, grounding it right back to reliever Matt Andriese.

Perhaps that performance was an overcorrection from the early season, which saw Lindor routinely serve balls to the opposite field with little impact. Swinging at multiple pitches out of the strike zone was likewise uncharacteristic for a player who exhibited excellent plate discipline throughout early April. Rojas dismissed the idea that Lindor’s troubles have anything to do with the pressure of switching teams or the unfamiliarity of changing leagues; the manager believes it’s an old-fashioned slump, plain and simple.

“I don’t think it’s something that’s going to be much of a task for him to overcome,” Rojas said “We just played Game 18 now out of 162. I think it’s just going to come one day where he clicks and he’s going to be hot. I just don’t want to jump the gun there and say that there’s anything affecting him other than he’s just going through a bad stretch now.”

Of course, Lindor is far from the only slumping hitter on a team that also includes Dominic Smith (currently in a 5-for-33 stretch), James McCann (4-for-22) and Kevin Pillar (3-for-23). Jeff McNeil did homer for the only run off Richards on Tuesday, and Michael Conforto appears to have corrected his own early-season issues. But the Mets continue to tread water overall, in large part because they remain last in the Majors in batting with runners in scoring position (.193).

“Hitting is very hard,” McNeil shrugged.

Tuesday, an announced crowd of 7,917 took that out on Lindor, who became just the latest scuffling newcomer to hear displeasure from fans. Hall of Famer Mike Piazza was routinely booed during his first half-season in Flushing. Carlos Beltrán, who became statistically the most productive free agent signing in franchise history, heard jeers throughout his career. Plenty of others did as well.

“Our fan base is very passionate. They support our team, and we feel that,” Rojas said. “It’s something that I think we’ve seen in the past here over the years when guys are going through a little bit of a struggle. But that’s kind of my thought of it. It’s our fan base being passionate as they are, wanting us to perform better to win games. I’m sure it’s not the last time we’ll hear a reaction from our fans.”

Overall, Lindor is batting .212 with two extra-base hits in 79 plate appearances. His exit velocities and launch angles have resulted in just one barreled ball in 60 attempts, which rates in the bottom 7 percent of the league.

Last week, hitting coach Chili Davis spent significant time watching video of Lindor, searching to correct fixes, and even trying a “tunnel drill” that Indians assistant hitting coach Victor Rodríguez recommended for the four-time All-Star. Like Rojas, Davis doesn’t doubt Lindor’s ability to shed these woes eventually. Lindor himself said recently that “it only takes one swing to feel like I’m in a good spot,” while Davis noted that “you want to let him kind of feel it out and find it.”

Considering the Mets are married to Lindor for the next 10-plus seasons, they don’t have much choice but to do exactly that.

“It’s going to come,” Lindor said last week. “I’ve just got to play games, and as a professional hitter, make the adjustments faster.”