The team said corresponding roster moves would be made Tuesday, when Houston begins a series at home against the St. Louis Cardinals.
The 24-year-old Gonzalez has a paltry .250 on-base percentage with four homers and 14 RBIs. The switch-hitter has started 50 of 77 games this season, making eight errors while mostly sharing time at shortstop with veteran Ronny Cedeno.
Gonzalez's most memorable moment came in the second game of the year when he singled with two outs in the ninth inning against Texas to break up Yu Darvish's bid for a perfect game.
The 28-year-old LeBlanc was designated for assignment, so the Astros have 10 days to trade, release or send him outright to the minors. He had a 9.82 ERA in three relief appearances for Houston after getting claimed off waivers from Miami on June 8.
LeBlanc is 1-5 with a 5.50 ERA in 16 major league games this year, including seven starts.