With no outs, Stefen Romero on second and the Mariners already holding a 1-0 lead, Cano lined a Cesar Ramos sinker off the yellow line painted atop the left-field fence. The baseball bounced back into the field of play as Cano cruised into second while Romero scored to make it 2-0.
Manager Lloyd McClendon walked out of the dugout and asked the umpiring crew to review if the baseball had cleared the fence. Officially, it took just 43 seconds before the call was confirmed. Cano was ordered to remain at second, but Romero's run still counted.
Cano didn't have to wait there long because moments later Hart hit a line drive to right-center that bounced off the same yellow line atop the fence. Perhaps thinking he had hit a home run, the designated hitter slowed briefly and was thrown out at second base.
McClendon again emerged from the dugout and asked the play be reviewed. After another short deliberation, the replay confirmed that Hart's drive landed on the yellow line atop the fence, then caromed back to right fielder Wil Myers.
Still, Cano scored from second to give the Mariners a 3-0 lead while Hart was credited with a single.
"That was pretty weird. You have nothing to lose by asking them to review them," said McClendon. "I kind of knew Robbie's wasn't [a home run], but I thought Corey's was because of that railing back there. You couldn't really see. I was a little disappointed with the fan that he didn't touch it. He should have been a better fielder and we would've had a double."
Adam Lewis is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.