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general::
Phrase(s): sub for someone or something
to substitute for someone or something. • I have to sub for Roger at work this weekend. • Will pliers sub for the wrench you wanted?, Phrase(s): sub someone for someone else [and] sub something for something else
to substitute someone for someone else or something for something else. • I will sub Chuck for Roger for this next play only. • We will sub the red ones for the blue ones.
McGrawhill's American Idioms And Phrasal Verbs