It could be nothing, but I couldn’t help but notice that moments after Soto was out of the game that the Iowa Cubs pinch hit for Welington Castillo. Castillo began the season rehabbing in High-A Daytona and has hit a combined .244/.324/.400. This is his 14th game for the Iowa Cubs and he played 12 for Daytona prior to getting re-called to AAA. ZiPS projected a .299 wOBA from Castillo entering the season so he’s not much better than Koyie Hill offensively.
UPDATE: Cubs.com says day to day for Soto so it’s probably nothing.