White Sox manager Ozzie Guillen said it was a product of the doubleheader and the need for everyone to play, as well as to "see what we can get out of him."
"Hopefully, he'll come out and help the ballclub to win the game," Guillen said.
Dunn has struggled throughout his disappointing season, batting just .163 with 11 home runs and 40 RBIs entering Monday. Over the last two years with the Nationals, Dunn hit 76 home runs while driving in 208 runs, and his batting average was 100 points higher.
White Sox center fielder Alex Rios also has struggled, batting .220 with eight home runs and 34 RBIs entering Monday. Rios' numbers are down from 2010, when he batted .284 with 21 homers and 88 RBIs.
Guillen said he believed Dunn and Rios owed it to themselves to do whatever is needed in the offseason to improve in 2012.
"Everybody learns by mistakes," Guillen said. "In the offseason, when you get older, you've got to work a little bit more, a little bit harder to try to get better.
"I don't think they should feel guilty about how much money they made without contributing. They want to, they were ready. But I think when the years go by and you're getting older, you have to take care of yourself a lot better."
Guillen also was asked if he thought the respective performances of Dunn and Rios were "embarrassing enough" for them to put in the extra work needed to improve next season.
While he could not answer for how Dunn or Rios felt, Guillen made it clear how he felt.
"They should be embarrassed," Guillen said. "I think they feel bad about the way they played this year."In the 2-1 Game 1 victory, Dunn went 0-for-3 with a strikeout. Rios went 3-for-5 with two runs scored in the 4-0 victory in Game 2.