Sanchez was back at AT&T Park on Wednesday after finishing a four-game rehab stint with Fresno. The rookie catcher has been out since July 17 with a sprained knee.
Manager Bruce Bochy said after the game that Sanchez will start behind the plate Thursday. Sanchez has hit .281 this season with two home runs and 24 RBIs in a backup role behind Buster Posey. Whiteside was called up to assume that role when Sanchez went down.
Loux has been sidelined since June 26 with a neck strain and has appeared in 11 games this season to post a 4.50 ERA in 16 innings.
Christian heads back to the Minors after going 6-for-37 (.167) in 21 games with the Giants, including only one hit in his last 22 at-bats.