I won’t say that won’t happen, but they will call back all the inactive reserves first. The 1st time you sign an active duty contract, you sign up for 8 years total. Everyone does. It normally is 4 years active and 4 years inactive, but sometimes it’s 5 and 3 or 6 and 2.
They called people back in '02, '03 during OEF/OIF. It’s easier to call people with prior training back then train 100% new one.