PHILADELPHIA — With the Philadelphia Phillies clinging to their playoff hopes and a one-run lead in the eighth inning on Wednesday night, the moment fell, of course, to the best player on the team, the one who had helped carry them this far.

When Pat Valaika of the Baltimore Orioles stroked a single onto the outfield grass and Pedro Severino rumbled toward home from second base, Phillies right fielder Bryce Harper scooped up the ball and fired a no-bounce throw to catcher J.T. Realmuto to cut down the potential game-tying run.

The fans in attendance at Citizens Bank Park chanted something that felt fitting for a superstar whose torrid second half has kept his team afloat and has perhaps thrust him near the top of the race for a certain end-of-year award he has won once before: “M.V.P.! M.V.P.!”

“He threw an absolute rocket to home plate,” Phillies first baseman Matt Vierling said after the 4-3 win. “It was a huge play, a clutch play by him. He’s a clutch player.”

For so long this season, the National League Most Valuable Player Award seemed earmarked for Fernando Tatis Jr., the superstar shortstop of the once exciting San Diego Padres. Tatis could still claim the prize because of his spectacular season overall — a .285 batting average, .988 on-base-plus-slugging percentage, 40 home runs, 25 stolen bases and 94 runs batted in. But as the Padres have faded out of the postseason race, Tatis’s play has been characterized by injuries, inconsistent play and dugout arguments.

From the start of August through Thursday, he hit .276, with a .912 O.P.S., nine home runs and 24 R.B.I. in 32 games. He missed 13 games last month because of a partially dislocated left shoulder.

In that same span, Harper has produced video-game-like numbers: a .345 average, 17 home runs, 42 R.B.I. and an M.L.B.-best 1.245 O.P.S. entering Thursday. (Only Kansas City Royals catcher Salvador Perez, with 20, has more home runs in the same period.) Including Thursday’s game, Harper has played in 63 straight games since July 17, weathering nicks and bruises and fatigue to be on the field every day for his Phillies (79-74) as the team sat two games behind the Atlanta Braves in the N.L. East with nine games left.

“I just got to keep going,” he said earlier this month. “That’s what this organization expects. That’s what these fans expect as well. No matter who’s on the mound or how I’m feeling, I got to keep posting every day.”

Harper’s surge has sent him shooting up the M.L.B. leaderboards for the season: .312 average (sixth), 33 home runs and a 1.050 O.P.S. (first).

“You know people say that they’re on fire and they’re hot for like a week or a couple of weeks ago,” said the Phillies’ first base coach, Paco Figueroa, who also oversees the outfield and base running in instruction. “He’s been hot since about since the All-Star break. And it’s impressive to watch. Every single pitch, everyone’s staring.”

While the A.L. M.V.P. race appears to be between the Los Angeles Angels pitcher and hitter extraordinaire Shohei Ohtani, who has been the favorite for much of this season, and Toronto Blue Jays first baseman Vladimir Guerrero Jr., who leads the A.L. in many offensive categories, the N.L. race feels far murkier.

Some advanced statistics position Harper as the best hitter in the N.L., followed by right fielder Juan Soto of the Washington Nationals (.325 average and 1.029 O.P.S.) and then Tatis. But if their entire bodies of work are taken into consideration, Tatis plays a more demanding position in the field and is a better base runner.

“There’s a lot of really good players in the National League, and I’m not saying anything against them, but I just get a chance to see what he does every day, and that’s an advantage for me,” Phillies Manager Joe Girardi said of Harper. “The walks, the base running, the defense, what he’s been able to do on a daily basis — so I’m a little partial.”

Labeled a prodigy since he was on the cover of Sports Illustrated at 16, Harper was the N.L. rookie of the year in 2012 with the Washington Nationals and was named M.V.P. in 2015, when he produced one of the most impressive offensive seasons in M.L.B. history: a .330 average with 42 home runs and a 1.109 O.P.S., with 9.7 WAR. At 22, he was the youngest unanimous M.V.P. in baseball history.

Since then, Harper has flirted with similar brilliance but has been slowed by injuries or inconsistencies. In 2019, the first year of his 13-year, $330 million deal with the Phillies, Harper hit .260 with an .882 O.P.S. and 35 home runs — strong production for most, but disappointing in light of the high bar set by his talent. This season, though, Harper, 28, has reminded those who had forgotten that he remains one of the very best hitters in baseball.

“Expectations are so high for him, so when he doesn’t have the super elite seasons like he’s having this year, you overlook it a little bit,” said the Phillies’ hitting coach, Joe Dillon, who was the Nationals’ assistant hitting coach during Harper’s final season in Washington, in 2018.

Dillon added later: “He’s been on a couple months’ run where he’s been as good as anybody, but you’re still not in awe of it for whatever reason, which is not fair to him. But that’s just expectations that have been around him. It takes a second to look back at what he’s doing to realize how special it is.”

Improved health has helped Harper’s defense and hitting, his coaches said. According to Dillon, Harper has used the lower half of his body better this season versus last, when he was dealing with a back injury for most of the pandemic-shortened 60-game season. Still, Harper hit .268 with 13 home runs, a .962 O.P.S. and led baseball with 49 walks — a reliable skill empowered by his sharp eye at the plate.

This season, Harper has overcome lingering back discomfort, a sore left wrist, getting hit in the face with a pitch and a bruised left forearm to play in 132 of the Phillies’ 153 games. (Tatis has played in 120 of the Padres’ 152.)

One of Harper’s biggest areas of improvement from past seasons: his production against off-speed pitches, which, according to Dillon, was proof that Harper has remained consistently under control with his violent left-handed swing rather than trying too hard. Against those pitches entering Thursday, Harper was hitting .329 this season — his highest mark since his M.V.P. season.

Against the Orioles on Tuesday, Baltimore Manager Brandon Hyde showed Harper the ultimate sign of respect during a game, a move routinely used against the slugger Barry Bonds in his prime: He intentionally walked Harper, the go-ahead run, in extra innings. Realmuto tripled to drive in the tying run and Harper, who scored from first to win the game, 3-2.

Harper has talked little about his success this season. He has said he will answer any questions about his season at the end, when he can sit down to look at his numbers to figure out how and where he can improve. Recently, he was unavailable for comment as he has stuck to a plan that has worked well for him: preparing for games in the indoor batting cages rather the traditional on-field batting practice.

Asked about the “M.V.P.!” chants he prompted after a Sept. 16 win in which he drove in four runs, Harper said it felt good to receive such a reception from fans but that he was more focused on the remaining weeks in the regular season.

Throughout the season, he said he didn’t let anyone in his life show him his statistics — not his wife, Kayla, or his father — his unofficial coach — or Girardi. He said his buddies knew not to text him about that. He said that if he were to see his numbers somewhere, such as on Instagram, he would flush them quickly out of his mind.

“I know it’s kind of crazy and it doesn’t make sense,” Harper said recently. “But I don’t like M.V.P. talk. I don’t like you looking at my numbers. I don’t like looking where I’m at or where I am in the second half or anything like that. I just want to play my game. I just want to show up every night, make sure I’m playing right field, batting third and helping this team win.”