Ventura had designated Hector Santiago as the closer at the beginning of the season, but Santiago had troubles in the role. Chris Sale was the closer briefly until he was returned to the starting rotation. Ventura also used a closer-by-committee approach.
Reed has recorded the White Sox's last four saves. He pitched two shutout ninth innings in the White Sox's sweep against the Chicago Cubs over the weekend.
Reed has allowed six runs, all of which came in one game, and has a 4.05 ERA in 16 appearances this season. He has also struck out 17 hitters in 13 1/3 innings.
"He's earned that," Ventura said before Wednesday's game with the Minnesota Twins. "I feel comfortable with him in there. That's who we'd be using if we're winning.
"Some nights he's up at 98 (mph), some nights it's 96, but still pretty good. Even when you'd look at him and think he doesn't have it, he's got it."
Despite Reed being just 23 and having pitched in just six games last season, Ventura felt he had the mental makeup for the role.
"I don't think he cares," Ventura said. "I just think he just wants the ball and pitches. From spring training on, anytime you hand him the ball he's not overwhelmed by any situation."
Ventura also believed it was best Reed waited his chance to be the closer.
"He could have been (the closer after spring training), but the way it worked I think it's going to be better for him in the long run," Ventura said.