Righty reliever Luis Guerrero reached 98 mph multiple times with his fastball and struck out two batters in a scoreless inning for the Red Sox on Tuesday.

Boston lost 6-1 to the Braves in Grapefruit League action.

The 24-year-old Guerrero made his MLB debut last Sept. 8. He didn’t allow an earned run in 10 innings over nine appearances for Boston. He limited opponents to six hits (one extra-base hit) and two walks while striking out nine. The 62 four-seam fastballs he threw averaged 97.5 mph.

Guerrero already has tossed two scoreless innings and punched out five in two outings this spring as he competes for a spot on the Opening Day roster.

“Strike throwing is the thing for him,” manager Alex Cora said here at CoolToday Park. “Something clicked last year halfway through it. He started throwing strikes. He throws hard and he pounds the strike zone. So those are good ones. We like those.”

Control was something holding him back in the minors. He averaged 6.5 walks per nine innings in the first half of 2024 for Triple-A Worcester.

But something did click for him during the second half when he struck out 50 and walked 13 in 35 ⅓ innings between Worcester and Boston. That was an average of 3.3 walks per nine innings in the second half between Worcester and Boston.

“We’ve been talking about all these guys,” Cora said when asked about Guerrero competing for a roster spot. “Versatility is important. As you see, we’ve got different angles in the bullpen. We’ve got a bunch of lefties. We’ll see how it plays out. But he put himself on the map. He’s a hard worker. His story is a good one. Now it’s like, let’s make a career out of it.”

As Cora mentioned, his story is a good one. Guerrero underwent right knee surgery as a 1-year-old and the muscles in the area are underdeveloped. He still walks with a limp. He also was a 17th round pick in 2021.