"In the long run, it's great news," Black said. "Are you kidding me? A broken hand or broken bones in the hand? Not good."
A Vance Worley 88-mph fastball caught Arenado on a 2-1 pitch in the fifth inning. Clearly in pain, Arenado walked toward the dugout as a Rockies trainer and Black examined him.
After several minutes, Arenado came off the field and headed for the clubhouse.
At the time, Arenado thought the injury was worse than results showed because he felt his hand tightening up. With the hand wrapped up postgame, he said it was swollen and that it was difficult to move his pinky.
"Luckily it's not broken, but it hurts a little bit," Arenado said. "It's gonna take some time. I don't know how many days, but hopefully a couple. It hurts pretty bad right now."
While it's still early, Arenado said the training staff didn't seem to think a disabled list stint would be necessary.
"They don't think so, which is good, but we'll see," Arenado said. "Hopefully these next couple days I can start gripping a bat or something. If not, then there's a possibility, probably."
The Rockies, in the thick of the National League Wild Card race, can ill afford to lose their All-Star third baseman for an extended period of time. Colorado is tied with the D-backs atop the Wild Card standings after Arizona's defeat to the Cubs.
Trevor Story entered the game to pinch-run for Arenado and remained at shortstop. Pat Valaika took over at third.
It marked the second straight game Arenado has exited early. He was ejected in the seventh inning of Saturday's 4-3 loss after tossing his bat on a called strike three on a check swing.
Patrick Pinak is a reporter for MLB.com based in Miami. This story was not subject to the approval of Major League Baseball or its clubs.