Right-hander Chris Beck was optioned to Charlotte prior to the All-Star break.
Fulmer, 22, stands as the White Sox top prospect per MLBPipeline.com and has been working out of the Birmingham starting rotation. After a somewhat wild start, brought about in Fulmer's opinion by slowing down his delivery too much, the right-hander has struck out 54 over his last 41 innings pitched with 17 walks.
His delivery has returned to the quicker pace that helped make Fulmer successful for three years at Vanderbilt. But Fulmer also stopped trying to be too fine on the mound, which sparked the turnaround.
"Once you hit adversity, you try to make a perfect pitch. You try to throw the ball in the exact spot that you want to. I feel like that digs you a deeper hole," Fulmer said. "Prior to the All-Star break, I went back to the simpler approach of continuing to throw my pitches in the strike zone and it definitely carried over after the break too.
"I want to compete with every pitch that I have. Throwing those in the strike zone and not trying to make the perfect pitch is how you get out of that."
Although the White Sox need a starter for Sunday's game against the Angels, who has yet to be announced by the team, Fulmer will be used out of the bullpen. He worked in relief for the Commodores as a freshman (all 26 appearances) and in 10 of his 26 games as a sophomore, following the relief-first path previously taken by White Sox starters Mark Buehrle, Chris Sale and Carlos Rodon.
"We're at a point where our guys felt he was ready to contribute right now," White Sox manager Robin Ventura said. "And we've been a little banged up in the bullpen so we're hoping he can fill that up and be useful."
"Not only was Carson ready for this next challenge, he was very likely to make us stronger in an area for need," White Sox general manager Rick Hahn said. "But for the long term, this was going to be good for him."
Morneau, 35, agreed to terms with the White Sox on a one-year contract on June 9 and was placed on the disabled list to continue his recovery from offseason surgery to repair the primary flexor in his left elbow. He appeared in eight games with Charlotte and Birmingham on his rehab assignment, finishing 4-for-23 with three walks, four strikeouts and two RBIs.
He is a career .282 hitter with 335 doubles, 241 home runs, 960 RBIs and 756 runs scored in 1,487 games over 13 Major League seasons with Minnesota (2003- 13), Pittsburgh (2013) and Colorado (2014-15), leading the National League with a .319 batting average in 2014.
Avisail Garcia started at DH Friday, and Ventura indicated that Morneau would face right-handers at the outset. Morneau grounded out to second as a pinch-hitter in the eighth of the White Sox 7-0 loss and will start Saturday.
"We'll see how it goes, we'll see how he feels," said Ventura, adding Morneau is not part of a platoon. "He's ready to go right now."
"There's only one way to really find out is to get in the box in a big league game," Morneau said. "I wouldn't have told them I thought I was ready if I didn't believe I was ready to come up here. To say it's going to be perfect or great from Day 1, I can't say that. But I'm here I believe I can help us win ballgames."