Winckowski will start Thursday's game against the Pirates, Alex Speier of The Boston Globe reports.
The 24-year-old was expected to piggyback Rich Hill in Wednesday's contest, but he'll instead start Thursday's series finale since Nathan Eovaldi (neck/shoulder) is banged up. Winckowski has made 11 starts for Boston this year and has a 4.69 ERA, 1.49 WHIP and 34:20 K:BB across 55.2 innings.