Kevin Gausman retired the first 14 hitters he faced at Camden Yards on Wednesday, and then he walked the bases loaded. Two hits followed, and three runs scored. Gausman recovered to throw two more scoreless innings, and after his Baltimore Orioles held on to beat the Los Angeles Angels, he said something revealing.

“I think that’s the thing aces do at this level,” Gausman said. “If they do have a bad inning, they come back and put up a zero.”

Gausman, 23, a right-hander, is not yet an ace. In 10 starts this season, he is 5-3 with a 3.70 earned run average, roughly in line with Baltimore’s other starters. The Orioles have a solid rotation; entering the weekend, their five healthy starters each had an E.R.A. below 4.00 but above 3.50.

What they lack is a proven No. 1. The two other American League division leaders added aces at the nonwaiver trading deadline on Thursday, with the Oakland Athletics trading for Jon Lester from Boston and the Detroit Tigers acquiring David Price from Tampa Bay. The Orioles grabbed a standout left-handed reliever, Andrew Miller, from the Red Sox but did not change their rotation.