He was assigned to Triple-A Sugar Land on Saturday.
“He’s a potential bat that can help us,” Astros manager Dusty Baker said. “Hopefully, he can unmask that talent that he has and at some point in time help us.”
The 31-year-old was regarded as one of the top infield prospects while with the Astros organization from 2011 to ’17 after being acquired in a trade with Philadelphia.
Singleton played in 114 big league games with Houston during 2014-15.
He appeared in 11 games with the Brewers this season but has spent the majority of the season with Triple-A Nashville. After being designated for assignment on Wednesday, he chose to become a free agent.
Singleton has hit .252 with 169 home runs, 645 RBIs and an .828 OPS in 1,064 minor league games.
Astros sign first baseman Jon Singleton to minor league deal