Yes, it's in the CBA. Section 11.8(b):
"A no-Trade clause or a no-move clause that is negotiated as part of an extension of an SPC entered into pursuant to Section 50.5(f) may become effective immediately upon registration of, but prior to the effective date of, such SPC extension, provided: (i) the Player would otherwise have been eligible as of the immediately preceding July 1 prior to signing the SPC extension to have a no-Trade or no-move clause pursuant to Section 11.8; and (ii) the Club and the Player, who are parties to such SPC extension, agree that the no-Trade or no-move clause is effective immediately upon execution of the SPC extension (or at some later date agreed to by the Club and the Player) and evidence such agreement in writing in the SPC."
So if you extend with your current club and could otherwise have an NMC/NTC, the clause in the extension can take effect immediately.