"We feel like he's going to come in here and make an impact," Astros general manager Dana Brown told reporters. "He could pitch some high pressure innings for us and his stuff is really good, very competitive, the ball moves all over the place. So we felt like he was a fit both for the team and his ability and to gel with our clubhouse makeup."
Graveman, 32, has appeared in 45 games this season, compiling a 3.48 ERA while giving up 33 hits in 44 innings. He slots in as a setup man in the Houston bullpen, the same role he had with the Astros in the second half of 2021 before inking a deal with the White Sox.
"I hated to see Graveman leave the first time," Astros manager Dusty Baker told reporters.
Graveman has one year remaining on a three-year, $24 million contract that he signed before the 2022 season.
Lee is hitting .283/.328/.406 with 18 doubles, five home runs, 32 RBIs, 37 runs scored and 12 stolen bases over 68 games this season with Triple-A Sugar Land in the Pacific Coast League. He currently is on the injured list with a strained right oblique.
Lee was selected by Houston with the No. 32 overall pick of the 2019 MLB draft out of the University of California, where he was a teammate of White Sox first baseman Andrew Vaughn.
"You hate to lose some of your prospects," Brown said. "At the end of the day, we thought we had a chance to really bridge the gap to the end of our bullpen and win more games."
The Associated Press contributed to this report.