Karen Finney, the Hillary Clinton campaign's advisor for communications and political outreach, tweeted a photo of Kaine and Brown chatting it up in their seats at Cleveland's Progressive Field.
"Two of the fans at tonight's game: @SenSherrodBrown @timkaine #WorldSeries," Finney wrote.
"Just two #Tribe fans hanging out #InTheCLE," she wrote.
Brown previously said, "As a lifelong Indians fan, I know that a World Series win for Cleveland is long overdue -– and this is the year. I’m proud to stand alongside my fellow Clevelanders in cheering for the Indians and I can’t wait to see my city bring home another championship."
While Clinton's running mate may be an Indians fan, she's a staunch Chicago Cubs fan, having been raised outside Chicago. This past weekend, her traveling press secretary tweeted a photo onboard the campaign aircraft capturing the moment she learned her beloved Cubs were heading to the World Series.
ABC News' Jessica Hopper contributed to this report.