A's third baseman Matt Chapman briefly stayed in Wednesday's game against the Kansas City Royals after taking a pitch off his left ear, but eventually exited after lining out in the second inning.
Royals pitcher Jakob Junis' 90.7 mph sinker knocked Chapman's helmet off his head, and the A's star initially remained in the game.
Chad Pinder replaced Chapman at third base in the bottom half of the second inning.
Chapman, 26, is in the midst of his most productive season in his three-year big league career. He made the All-Star Game for the first time, and already has clubbed a career-high 30 home runs and 74 RBI. The 2014 first-round pick won the AL Platinum Glove as the league's best defender in 2018, and he led all AL infielders with 18 defensive runs saved (DRS) entering Wednesday.
If Chapman has concussion symptoms, he can first be placed on the 7-day injured list. A source confirmed to NBC Sports California's Ben Ross on Wednesday that the A's are set to call up third baseman Shelden Neuse, the team's No. 8 prospect. Oakland would need to make a corresponding move to bring him on to the 40-man roster.