When the Rams traded a boatload of draft picks for the right to select first overall in the 2016 draft and took Cal quarterback Jared Goff, they likely expected him to have a better rookie season than he did. When you give up two first-round picks, two second-round picks and two third-round picks for one player, you want him to look at least marginally ready for prime time.
To put it succinctly, Goff didn't. The problems with his game evident during his time at Cal—most notably his severe timing and accuracy issues—showed up in the NFL.