Baltimore ? The ball trickled up the third-base line, rolling so slowly that Baltimore third baseman Wilson Betemit could have counted the stitches.

Betemit hoped the ball would roll foul as it spun in the chalk. It stayed fair. And thanks to a good bit of hustle, Eric Hosmer ended up on second base with a 55-foot double that played a key role in Kansas City’s 4-3 comeback victory over the Orioles on Saturday.

Hosmer went 3-for-4 with two RBIs to help the Royals make up a three-run deficit. He singled in the tiebreaking run in the eighth inning, but his swinging bunt in the seventh was no less significant.

With the Orioles up 3-2, Hosmer hit the slow-roller that turned into a unique two-base hit.

“Greatest double I’ve ever seen,” Royals manager Ned Yost said. “That’s a heads up play by Hosmer to be able to get to second base.”

Humberto Quintero followed with an RBI double down the left-field line to make it 3-all.

“It’s one of those things where you’re just running down the box hoping it stays fair,” Hosmer said of his hit. “To be honest with you, I kept shuffling, shuffling, and I realized I had a chance at second. I saw his back turned, so I just decided to take off.”

Betemit committed himself to letting the bunt roll, a decision that did not pay off.

“I can do nothing about it. It stayed on the line,” Betemit said. “I had to wait, fair or foul, and it stayed inside. I didn’t have time to get the ball to second to get the out.”

In the Kansas City eighth, Mike Moustakas led off with a single off Pedro Strop (3-2), who came in with 13 straight scoreless appearances. A walk and a single loaded the bases for Hosmer, who lined a single to left.

Greg Holland (1-2) pitched the seventh, and Jonathan Broxton got three outs for his ninth save in 11 chances.

Chris Davis and J.J. Hardy hit solo home runs for the Orioles, and Adam Jones extended his career-best hitting streak to 17 with a third-inning triple. It was only the second time this season that Baltimore lost a game in which it homered.

Kansas City closed to 3-1 in the fifth inning when Johnny Giavotella led off with a double and scored on a single by Hosmer.

Billy Butler homered off Orioles starter Wei-Yin Chen in the sixth to make it 3-2.

Then came Hosmer’s seventh-inning dash.

“Usually, when the ball comes off the grass there at our park it goes foul,” Orioles manager Buck Showalter said. “The only thing you can do is line it up where your body is facing the runner as opposed to behind him so you can see. But I’d say a high percentage of time that ball rolls foul.”