The Associated Press (h/t ESPN.com) reported the news, noting Ramirez exited after an inside pitch from Warwick Saupold hit his bat and then his arm. According to Jordan Bastian of MLB.com, umpires used replay to overturn what was initially ruled a hit by pitch and deem it a foul ball.
The AP said Ramirez will likely have precautionary X-rays.
The third and second baseman has been one of the most important hitters for the defending American League champions this season and was slashing .306/.359/.560 entering Monday's contest. He drilled his 26th home run of the season in the fourth inning before exiting with the injury in the sixth.
The AL Central leaders will rely on Giovanny Urshela, Yandy Diaz and Erik Gonzalez in the infield if Ramirez misses time.
The Indians are cruising to the division title, as they extended their winning streak to a head-turning 19 games Monday. They can afford for Ramirez to miss some time in the immediate future, but they will need him back and healthy in October as they look to build on last year's run to the Fall Classic and win the World Series for the first time since 1948.