KANSAS CITY -- The Royals were only able to add two extra players to their big league unit on Wednesday, as the annual September expansion of rosters was trimmed down to just 28 this season. Kansas City’s two additions, Jackson Kowar and Adalberto Mondesi, were called on right away as they both found themselves in the starting lineup.

And while the Royals may have had a few more names that they wanted to add into the mix, Kowar and Mondesi's performances certainly did not leave them yearning for more.

Kowar turned in easily the best start of his young career, tossing six innings and allowing no earned runs while striking out a career-high six, and Mondesi fueled the offense with a homer and two runs scored. The Royals couldn’t turn their contributions into a victory, however, as they fell 5-3 to Cleveland in 11 innings.

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Kowar, who was promoted from Triple-A Omaha earlier in the day, took the mound with three big league outings already under his belt. They were largely forgettable, however, as he held a 18.00 ERA through five innings pitched.

The story couldn’t have been more different on Wednesday. Kowar allowed four hits and walked three, but thanks in part to his benchmark six K’s, was able to limit the damage from Cleveland’s offense. The two unearned runs on his tab came when Michael A. Taylor dropped a fly ball off the bat of Andrés Giménez for an error in the fifth.

"What an amazing turnaround from when we last saw him," manager Mike Matheny said. "Came out with confidence, came out establishing that the fastball -- not just establishing the fastball, but establishing a very, very good fastball with good life, not afraid to pound the strike zone, not pitching away from contact, just made everything else better."

Kowar agrees with his skipper's assessment, both in terms of how he performed and how his outing compared to the last time he was in The Show.

"A lot more enjoyable, especially I mean, as the starting pitcher, being able to come out of the game just giving your team a chance to win is really all you can ask for," Kowar said. "So, definitely, felt good to go deep into a ballgame and really give us a chance to win."

Kowar's uptick largely came via better control, namely of his changeup and slider. He also attributed his refined performance to a calmer demeanor, as he was no longer preoccupied with the fact that he was finally debuting in the Majors and everything that comes with that.

"The heart rate's a little lower," Kowar said. "It's obviously a little easier the second time around, just with having been here, been out there, been in the clubhouse before. All that unknown stuff is kind of out the window, and it just felt a lot more just like pitching a baseball game and competing."

Kowar couldn’t earn his first career win, as Yu Chang clubbed a pinch-hit homer to tie it in the seventh off Jake Brentz, who was also activated off the IL on Wednesday. The Royals had a chance to win it in the bottom of the 10th, when an error and a walk loaded the bases with no outs. But a strikeout and a pair of popups ended the threat there, and Cleveland brought in two runs in the top of the next frame to pull ahead.

Mondesi had experienced more statistical success this season than Kowar, but was not without his share of speed bumps. He entered the game batting .361 with a 1.212 OPS, but had appeared in just 10 games due to a pair of oblique strains that resulted in IL stints.

Activated on Wednesday, Mondesi showed no signs of rust; he hit the ground running in his first at-bat, sending a line drive just foul that may have had the distance to go out before singling up the middle. After advancing to second, he stole third, and then came around to score on an errant throw by catcher Austin Hedges. In his next at-bat, he drove another ball toward the fence, but this time left no doubt about where it was headed -- he launched it a Statcast-projected 422 feet straight into a fan’s glove right in front of the outfield fountains.

"He gets up there and hits a single, and it's just like, 'Is it that easy?'" Matheny said. "And then next thing you know, with the home run. He gets on base and makes things happen. Puts pressure on, draws a bad throw, scores and it just -- that's the kind of player he is. But watching the ball jump out of the park, once again, shows us how this guy, he's got a special talent."

Mondesi's impact on the game is undeniable; it's just a question of how many games he's able to make that impact in. He’s played in only 11 of the Royals’ 132 contests this season, and while the team has been able to fill in the gaps defensively, they desperately miss his presence with the bat at the top of the order.

Whit Merrifield knows that, and knows that if Mondesi is able to stay healthy and continue to perform the way he did on Wednesday and in his other 10 appearances this year, special things will come.

"Well we all know what kind of talent he is and what kind of spark he brings to the lineup when he's in it," Merrifield said. "Just stepped right back in and got a couple knocks, stole a bag and hit a homer ... it was great to see him back, and yeah, got to keep him on the field. If we do that, it'll be a lot of fun to watch."