"We may or may not see him when we play them," Astros manager A.J. Hinch said, "but no thoughts on that."
Drafted by the Astros in the 20th round of the 2011 Draft, Duffy was a part of Houston's Opening Day roster. He only played three games for Houston this season, going 0-for-3 in three at-bats, before being sent to Triple-A Fresno.
With the Grizzlies, Duffy was batting .226 with 60 hits, 30 RBIs and six home runs in 74 games.
The Astros and Rangers are locked in a tight race for the American League West lead. Entering Saturday, Houston trailed the Rangers by only 2 1/2 games after trailing by 11 games on June 20.
Jordan Ray is a reporter for MLB.com based in Houston.