Coby Mayo was heading to Baltimore yesterday as the Orioles posted their lineup against Royals left-hander Kris Bubic, the owner of reverse splits and a dominant start against them last month in Kansas City.

Emmanuel Rivera started at third base with Jordan Westburg and now Ramón Urías on the injured list. The Royals close out the series today with right-hander Michael Lorenzen, who shows a slight reversal in career splits with right-handers batting .252 with a .715 OPS and left-handers batting .231 with a .705 OPS.

The splits are more pronounced this season. Right-handers are batting .279 with an .884 OPS and left-handers are batting .225 with a .559 OPS in his six starts.

Mayo has a chance to crack the lineup, whether at third base or first. He’s made an equal number of starts at each position with Triple-A Norfolk, and observers say he’s improved.

One of them sat in the Orioles’ clubhouse yesterday, with a better shot at starting today – weather permitting, of course – because Adley Rutschman caught last night.

“He’s a young guy still,” said Maverick Handley. “I think the bat is real, it’s still there. His defense is ever improving. I think he’s been playing a little more first and I’ve definitely seen an uptick in defense there. Playing third or first, I know they’re both corner infield positions but they’re drastically different. Drastically different. So seeing him getting more comfortable over at first moving toward balls …

“I know one of the most uncomfortable balls when somebody first gets over there is the ball hit to your right because you’re like, ‘Is the second baseman there? Should I go to the bag?’ There’s little decision-making things. I see those reps happening and he’s getting better, which is great.”

“I’m always working hard," Mayo said after last night's 4-0 loss. "The coaching staff does a really good job trying to put an emphasis just on defense, because if you can play really good defense in this game, you’re gonna stick around for a while. I think I’m a pretty good hitter and I’d like to think that I can be a really, really good defender in this league, too, so just trying to balance out both and just be a complete, really good player.”

Mayo didn’t hit in spring training until it was too late, finishing 8-for-42 but going 7-for-19 in his last eight games. He probably wouldn’t have made the club anyway because of the crowded infield, even with Gunnar Henderson headed to the injured list, but he felt frustrated at a return trip to Norfolk.

Rather than sulk, Mayo came out swinging. He batted .255/.353/.539 with seven doubles, two triples, six home runs and 21 RBIs in 28 games. Ten of his hits came in his last eight games.

“I think he had a great attitude,” Handley said. “I never saw him pouting, which I think was a real good indication of where he was at in his head space.”

The Orioles have a .490 OPS against left-handed pitching that’s the lowest in the majors. Stats from the minors don’t automatically transfer to baseball’s highest level – the quality of arms tends to rise with the jump – but Mayo was 9-for-17 (.529) with a 2.050 OPS in 19 plate appearances against left-handers at Triple-A. He had two doubles, a triple and four home runs.

“Obviously, we do a lot of preparation, talking in the offseason just about that can be a big role for me in my career, being a lefty (facing) power hitter, just a really good hitter in general,” he said. “Being stingy with swing decisions and whatnot. I think just narrowing the zone down in Triple-A and trying to make them come to me, where last year in Triple-A, I hit well off lefties last year, but this year hopefully there’s more power.

“I think last year I only had one homer off a lefty and I already have four this year. Good to see signs of improvement in that department and just look to continue with that.”

Mayo pinch-hit for Heston Kjerstad last night with a runner on first base and no outs in the seventh and popped up against left-hander Daniel Lynch IV. He stayed in the game at third base and struck out against right-hander John Schreiber to end it.

“I think every player wants an opportunity to show their talent and showcase their abilities to be a really good major league baseball player. And I think I’ve done a really good job of being a really good minor league player,” Mayo said. “Now it’s about becoming a really good, consistent major league player.”

Executive vice president/general manager Mike Elias said Friday that Mayo was “really close” to another promotion, but he added, "I think it’s really important for us as we look at the timing of when that next major league opportunity is going to be, that it’s kind of the right opportunity for him if we’re able to control that.”

Urías’ hamstring forced the Orioles’ hand.

Elias said he wanted Mayo to have “the right pathway.” The club didn’t want to set him up for another failure and have to option him again as if he’s just another shuttle player. They could face a roster decision Wednesday when Westburg is eligible to return from the injured list. We don’t know whether he’ll be ready.

Mayo could go back down or the Orioles could designate Rivera for assignment. Rivera cleared waivers in February and accepted his outright assignment. All he’s done is hit, including last night’s single, since the Orioles claimed him on waivers from the Marlins on Aug. 21.

They’re both corner infielders, but only one is the 12^th-rated prospect in baseball.