Even before Jorge Mateo booted a routine ground ball to shortstop that might’ve turned into an inning-ending double play, right-hander Grayson Rodriguez found the fourth inning Friday night to be a grind.

The rookie Orioles starter had allowed three runs in the frame and five overall to that point. It wasn’t his best — Rodriguez had shown that this week against the Toronto Blue Jays — but it also wouldn’t have been a disaster. That is, if Mateo had made the routine play.

Instead of walking to the dugout with his team still in reach, Rodriguez watched his very next pitch to Corey Seager, a cutter over the heart of the zone, leave the yard in a hurry for a grand slam. It was the kind of unraveling display that can be expected from a young player still learning how to overcome adversity. His rookie season will be this way — the good and bad commingling, sometimes in the same week.

Undoubtedly, the 3 1/3 innings in Friday’s 12-2 loss to the Texas Rangers made up the worst start of Rodriguez’s career. He yelled into his glove while walking off the mound and then into the dugout and down the tunnel toward the clubhouse.

“Just kind of the inconsistency is a little frustrating,” Rodriguez said. “We know it’s there. Just got to go out and do better than that.”

It might not have gotten to that point, though, had Mateo made a play he has made countless times.

Then again, the next learning step for Rodriguez will be to bail himself out when the teammates behind him can’t. A better location on his cutter, perhaps, and Seager doesn’t blast a grand slam. Earlier in the frame, a triple by Josh Jung led to a single from Josh Smith one pitch later. And, one pitch after that, Rodriguez allowed a two-run homer to Robbie Grossman.

The hit parade off Rodriguez came in quick succession, and it will take more starts and more seasoning before he can separate the play that just concluded from the pitch he’s about to throw.

The fourth inning compounded on him. One negative turned into another. The cycle continued, spiraling out of control, until Rodriguez was pulled before the eight-run inning ended.

“Just making pitches when it’s most important,” Rodriguez said. “Obviously, when it’s guys on base and in scoring position, I need to be a little bit more careful with the pitches.”

Against the Blue Jays, Rodriguez allowed four hits and two runs in five innings. The start before that against the Los Angeles Angels, he was roughed up on his way to eight runs on nine hits in 3 1/3 frames. His first 10 starts to his major league career have largely followed that pattern — and it’s not much of a surprise.

Rookie seasons for starting pitchers, even those so highly regarded, can be fickle. For some of Baltimore’s other starters, such as Dean Kremer and Kyle Bradish, these rough outings were more norm than anomaly.

But they did it when the Orioles weren’t holding the second-best record in Major League Baseball, so the magnifying glass is lowered on Rodriguez’s every start. At times, the 23-year-old sparkles. To end April, he pitched 10 scoreless innings in consecutive starts against the Detroit Tigers, for instance.

“That’s what’s disappointing,” manager Brandon Hyde said. “For me, his last start was so competitive and he was attacking in the strike zone, and even his misses were just off. Tonight, it was a lot of ball out of hand, a lot of fastballs up to left-handed hitters. You can out-stuff people below us, but here you have to be — even though your stuff’s good — you have to be able to command the baseball, and he’s just had a few appearances where he hasn’t been able to do that.”

Baltimore entered Friday with the positive energy that comes with executive vice president and general manager Mike Elias saying the club is looking to buy at the trade deadline. The Orioles are coming off four straight series wins against American League East opposition and finished a road trip in Toronto and New York with a 5-1 record.

Friday’s loss — however lopsided the fourth inning made it — doesn’t change the overarching positives. Even with outfielder Ryan McKenna lobbing in 35 mph strikes to finish the ninth inning, Friday’s loss is just one game in 162.

The same goes for Rodriguez. It’s one start of many.

“Night’s like tonight happen,” Hyde said. “We’ll flush it, come back tomorrow. It’s baseball. This happens. But I’m really pleased with how competitive we’ve been so far.”

andy.kostka@thebaltimorebanner.com