Pirates second baseman Neil Walker has been sent back to Pittsburgh to undergo more tests, the Pittsburgh Tribune-Review 's Rob Biertempfel writes .
Walker left Friday night's game after a collision with Ryan Church. It was later revealed Walker suffered a concussion on the play.
Walker is hitting .295/.325/.464 with three home runs and 12 RBI in 28 games for the Pirates so far this season.
-- C. Trent Rosecrans
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