Marinaccio was placed on the 15-day injured list Tuesday with a stress reaction in his right shin.
Marinaccio has had a strong rookie season, posting a 2.05 ERA and a 30.9 percent strikeout rate in 44 innings of work. The injury means he'll end the season with those numbers and will remain unavailable for the ALDS, but it's possible he returns for the ALCS should the Yankees get that far.