A second round pick is not that steep of a price to pay for a shot at a competent QB - they spent a 3rd rounder on Beathard. If Garoppolo flames out they can easily wash their hands of this and move on (they'll most likely have the 1st or 2nd overall pick). If he plays well then they can franchise tag him, which would give them quite a few options - sign him to a long-term deal, sign another free agent QB (Hello Kirk Cousins!) and deal him for more then they paid for him, or draft a QB. I think this move makes sense for Niners, as it gives them options without having to go all in on a unknown quantity. The next 8 weeks for Garoppolo will be the audition for the rest of his career.