The White Sox optioned Nastrini to Triple-A Charlotte on Tuesday.
The right-hander worked as a bulk reliever Monday against the Guardians and delivered his best outing of the campaign with 3.1 scoreless innings, but he'll still lose his place on the MLB roster. Nastrini hasn't been effective in his nine big-league appearances (eight starts) this season and has a 7.07 ERA, 1.91 WHIP and 26:36 K:BB in 35.2 innings.