Abreu was dealing with soreness in that same ankle for the last couple of days, and he was going to sit out on Sunday anyway, but now he'll miss the next couple weeks with his DL stint. Meanwhile, the Sox brought outfielder Adam Eaton off the DL to fill the roster spot, which lessens the blow a bit.
Through 44 games, Abreu has been one of the most dangerous hitters in the majors, hitting 15 home runs and driving in 42 runs, both of which currently lead the league. He's also slugging a league-leading .595 and has played a significant role in the White Sox's 21-23 record, which comes one year removed from a 63-99 finish—third worst in baseball.
Eaton, the team's leadoff hitter before landing on the disabled list on May 3, has proven to be a valuable part of the Sox lineup as well, posting a .363 OBP while scoring 20 runs in just 113 plate appearances.
At the very least, the time off should give Abreu's ankle the chance to fully heal, instead of taking it day-by-day and risking further aggravation.
The move also gives veteran Paul Konerko a chance for more playing time in his final big league season, though Konerko has struggled at the plate this season with a .208/.259/.333 line across 54 plate appearances.