If someone was sentenced to 7 months but just got a resisting arrest charge thrown on them, will it increase their time in jail?

This will not immediately add to the original sentence, but it poses a problem when the new charge is heard by a judge. This is where the new case by itself would probably sent to probation instead of incarceration. WIth two strikes in such a short period of time could make the resisting charge result into another several month stay in county jail