[A] designated hitter will be used in the All-Star game every year, including in NL cities. The DH has been used since 1989 when the All-Star game was played in AL ballparks. There would have been a DH anyway for this year’s game.
also,
Another change is that a pitcher who starts on the final Sunday before the All-Star break will be ineligible to pitch in the All-Star game and will be replaced on the roster, Major League Baseball said in a change announced Wednesday.