Not Understanding The Concept

Jim Leyland just pulled a double switch, moving his pitcher into the number eight spot in the lineup, replacing Brandon Inge, who made the last out of the eighth inning. This is a move made to not have to lead off the ninth, trailing by at least 4-0, with the pitchers' spot in the lineup.

The hitter chosen by Leyland to fill the ninth slot, and thus make this critical leadoff at-bat? Neifi Perez.