The former Real Madrid coach was left aghast that the Wales star went to replace his footwear against Sevilla in the build-up to Carlos Bacca's winning goal.
Bale moved to the sidelines to change his footwear while play was continuing in the second half at the Ramon Sanchez Pizjuan, allowing Ivan Rakitic to launch a counterattack down the Welshman's vacated flank and set up Carlos Bacca for the winning goal.
Toshack believes his compatriot deserves the wrath of coach Carlo Ancelotti and claims such a decision would never have been allowed during his playing days with Liverpool.
"Bale changing his boots 70 minutes in - leaving the pitch to change them - is criminal. The coach should give him the silent treatment for a month," Toshack is quoted as saying by Marca. "At Liverpool, the club I grew up at, it would be simply inconceivable."
Defeat to Sevilla saw Madrid fall three points behind Liga leader Atletico Madrid ahead of a clash with Rayo Vallecano on Saturday.