What sparked Jackson Merrill's huge second half in 2026?

Fernando Tatis Jr.'s amazing in-season turnaround was one of the top stories for the Padres in 2026. MLB.com's Brent Maguire recently broke it all down here.

But he wasn't the only San Diego outfielder who turned it on at the plate as the season progressed. In mid-July, about six weeks after Tatis began getting his year back on track, Jackson Merrill was mired in what had been a season-long slump, hitting .214 with an OPS slightly above .600.

Then something clicked, and the 2024 National League Rookie of the Year runner-up looked once again like one of the most promising young players in the game.

Let's take a look at what happened and pose a big question that awaits Merrill in 2027.

• Tatis, Miller represent Padres on All-MLB First Team

What happened in 2026?
.254/.303/.440 slash line, 26 HR, 27 SB, 4.2 FanGraphs WAR in 158 G

That slash line is much more impressive when you consider that it was .214/.271/.341 through Merrill's first 95 games this past season. His fWAR at that point was 1.0, largely because of his plus defense in center field, which has been a constant throughout his three-year career. His +26 fielding run value is tied for fourth among qualified outfielders since the start of 2024.

But offensively, Merrill was way under water. Entering July 19, he had a 72 wRC+ (100 is league average). That ranked 145th out of 150 qualified hitters.

Merrill then slugged two homers that afternoon as part of a four-hit game as the Padres blew out the Royals. Everything was about to change.

From that day on, Merrill slashed .316/.351/.590 across 263 plate appearances. His 156 wRC+ sat ninth in MLB. His 3.2 fWAR was the Majors' fifth-best mark. No matter how you sliced it, the 23-year-old was a top-10 position player over the final two-plus months of the season.

Key stat
74.2 mph average bat speed in September 2026

You could fill a boat on San Diego Bay with all of the stats that showcase Merrill's second half improvement. There's too many to choose from. In general, he hit more fly balls and he hit the ball harder than in the first half.

A big reason for that increased force was Merrill's increase in bat speed. For the season, his 73.4 mph average bat speed was a 1.5 mph jump from 2025 and ranked in the 64th percentile of MLB. But consider that through August, Merrill's bat averaged 73.3 mph -- and then he upped it by nearly a full tick in September. His fast-swing rate leapt from 30.3% to 41.6% in the closing month.

The result? A .333 average and a .567 slugging percentage -- Merrill's best numbers in any month in which he's had at least 50 plate appearances. His 60.6% hard-hit rate -- another personal best for any month -- was the fourth best in MLB (min. 50 PA). His robust 19.7% barrel rate tied for fifth.

When you swing hard and make optimal contact, good things often occur. Merrill proved that down the stretch.

Biggest question for 2027
Can his approach lead to sustainable success?

There was an unbridled quality to how Merrill finished the season. Not just because he was often swinging with all of his might, but because he was also doing so at pitches you typically don't want to swing at.

Merrill's chase rate in July and August was north of 40%, including a career-worst 42.0% in that latter month. It was at 38.4% in September. For comparison, only seven hitters had a chase rate in the 40s in 2026 (min. 1,000 out-of-zone pitches seen).

Furthermore, Merrill's whiff rates in August and September were among the highest of his career. In the final month, he pushed past 30% for just the second time in the Majors.

Merrill has often carried high chase rates and low walk rates. Now he has thrown elevated whiff rates into the mix over the past two seasons and especially over the final two months of '26. It's a reckless approach -- but it's one that clearly worked for him. If Merrill stays healthy and retains his bat speed gains, what he's swinging at may not ultimately matter much; he's going to do damage.