BALTIMORE -- None of Grayson Rodriguez’s three breaking pitches (changeup, curveball, slider) were proving to be deceptive enough. For that reason, the Baltimore right-hander could quickly tell that Tuesday had the potential to be a troublesome night for him at Camden Yards.

A well-located changeup near the bottom of the strike zone was smacked by Boston’s Wilyer Abreu for a first-inning home run. Two pitches later, Rodriguez threw a slider that caught too much of the plate and was belted to deep center field by Rob Refsnyder for a double.

After allowing four runs on six hits, one walk and a hit-by-pitch over the first two frames, Rodriguez knew it was time to modify his game plan.

“Obviously, I had to make an adjustment. They were hitting soft [pitches] pretty well,” Rodriguez said. “Really just kind of flipping that to hard stuff up in the zone.”

Rodriguez’s electric four-seam fastball (which averaged 96.2 mph and maxed out at 97.7, per Statcast) saved his performance.

Relying on a heavy dose of heaters from the third through the sixth, Rodriguez finished with a career-high 10 strikeouts over a 90-pitch outing in the Orioles’ 8-3 loss. The 24-year-old induced 18 whiffs, including 12 with his four-seamer -- both of which rank as career bests.

“The fastball helped me tremendously. It got me through that outing,” said Rodriguez, who didn’t allow a run and gave up only one hit over his final four innings. “If I didn’t have it today, I think it would have been a lot shorter and a lot worse of an outing.”

Of Rodriguez’s 43 pitches over the first two frames, 24 were fastballs (55.8%). Even that high of a percentage wasn’t enough to yield strong results, as the Red Sox's hitters were capitalizing on other offerings, recording four of their first six hits on breaking pitches.

So Rodriguez turned up the heat. He struck out the side in the third, when he threw 13 fastballs among 18 pitches. He delivered another 1-2-3 inning in an 11-pitch fourth that featured nine four-seamers and a pair of strikeouts.

Rodriguez threw seven fastballs in a nine-pitch fifth, stranding a runner at third. He capped the outing with a nine-pitch sixth, utilizing four heaters while again retiring the side in order.

Over the final four innings, Rodriguez threw 70.2% fastballs (33 of 47). His overall four-seam usage of 63.3% ranked second among his 32 MLB starts, behind only an outing vs. the Rays last Sept. 16, when he threw 69.5% heaters.

“He got hit hard the first couple of innings, he was leaving some balls in the middle part of the plate and they hit some balls hard against him,” manager Brandon Hyde said. “But I thought he made some really good adjustments there after the second inning, and the next four were outstanding.”

Every start is still a learning experience for Rodriguez, a 2018 first-round Draft pick and former top prospect who has logged only 173 big league innings. He’s learning how to grind through outings when he may not have his best stuff.

It was a struggle on April 23, when Rodriguez allowed seven runs on 11 hits and pitched a season-low 4 1/3 innings vs. the Angels. But last Thursday, he worked five frames of two-run ball against the White Sox despite issuing five walks.

“For me, that’s one of the strides he’s made so far, is quick adjustments, not letting it snowball on him,” Hyde said.

Baltimore’s deficit vs. Boston remained 4-3 while Rodriguez kept the O’s in the game. They missed an opportunity to get the righty a win when they loaded the bases with no outs in the sixth and failed to score a run.

The Red Sox blew the game open in the late innings, plating a run in the eighth and three more in the ninth against the Orioles’ bullpen, which deployed three relievers after Rodriguez’s exit.

It could have been worse for Baltimore’s relief corps, though. If Rodriguez had been pulled in the third or fourth, the O’s would have needed more arms to get through the night, which wouldn’t have been ideal early in a stretch of 43 games in 45 days through the end of June.

“The most positive thing about this outing was going six innings, trying to save innings for the bullpen,” Rodriguez said. “I know it can get tiring down there, so any time a starter goes out, I think six innings is the bottom line of where we’re trying to get to.”