As talented as Sixto Sánchez is, the Marlins’ rookie right-hander learned a tough lesson on Friday in a 5-0 loss to the Nationals in Game 1 of a doubleheader at Marlins Park.

Even on a day he was throwing well, in terms of velocity and pitch movement, he still wasn’t rewarded with favorable results.

In his sixth big league start, Sánchez had his statically worst performance. The five runs and eight hits allowed are both career highs. The four innings and two strikeouts were lows.

“I thought he had his 'A' stuff yesterday, quite honestly,” Marlins manager Don Mattingly said on a Zoom call Saturday. “Where he’s going to make the biggest strides over the long haul is knowing how his pitches work and how that combination works, and being able to adjust on the fly a little bit.”

Sánchez is 3-2 with a 2.75 ERA with 31 strikeouts in 36 innings. The quality of his stuff remains high, and he’s one of the promising young pitchers in the game. According to Statcast, he has an expected ERA of 2.86, which takes into account the quality of contact he allows. His xERA is in the top nine percent.

The Nationals were the first team to see the hard-throwing rookie twice. They went on attack mode early, being aggressive early in counts.

Of Sánchez’s 68 pitches, the Nationals swung at 40 of them.

According to Statcast, of all MLB starters who have thrown at least 100 pitches, Sánchez is getting swings on either the first or second pitch 44.7 percent of the time, which is second to Michael Pineda’s 45.3 percent. That percentage for Sánchez rose from 43.6 percent entering the game.

The fact that Sánchez throws hard (four-seam fastball average 98.6 mph) and throws so many strikes has hitters trying to jump him early in counts.

Baseball Reference underscores this in the split that measures when batters swing or take a first pitch. When batters swing at the first pitch against Sánchez, they have a .358 batting average (19-for-53). When they take his first pitch, their average is .167 (13-for-78).

“His game is not going to get easier, it’s going to get harder, especially for a guy like Sixto,” Mattingly said. “This guy already is kind of making a name for himself. It’s going to be like they’re going to want to hit him. They’re going to bear down more on him than they would against anybody else.”

Even though he has a high early-swing rate against him doesn’t mean Sánchez shouldn’t continue to attack the zone. And Mattingly noted that throwing a purposeful ball from time to time also can keep hitters honest.

“He throws so many strikes and he can throw a strike when he wants,” Mattingly said. “So how does he use out of the zone?”

The day after an outing, each Miami starter goes over the game with pitching coach Mel Stottlemyre Jr.

That means Sánchez already has discussed ideas on adjustments he may make for his next scheduled start, which is Wednesday at the Braves.

“That’s where he’s going to have an advantage, because he can throw strikes,” Mattingly said. “If he needs to waste a pitch, use it as a purpose. If he has to go in for a ball and run him off the plate a little bit, and then go off the plate, or double up in there.

“He has to be able to play the game a little bit with them. He has the stuff, and he throws enough strikes that he is capable of doing that.”

Worth noting
• Left-hander Daniel Castano, who started Game 2 on Friday, was returned to the alternate training site in Jupiter, Fla. The move was anticipated, because he was added as the 29th man for the doubleheader.

• Utility player Jon Berti (lacerated right index finger) is eligible to be reinstated on Sunday.