The Athletics optioned Alvarez to Triple-A Las Vegas on Saturday.
The 30-year-old right-handed hitter was in the lineup Thursday at first base against a lefty starter, but that was his lone start during this latest stint with the big club. Alvarez is slashing .306/.402/.580 with 14 home runs and an 18 percent strikeout rate in 62 games at Triple-A this season.