Jrry32 makes a compelling case but I am more like Dog in that I think the real key is whether Fisher gives Goff the opportunity (i.e. number of passing attempts vs number of rushes). It is hard for me to see Fisher throwing the ball 58% of the time as Bradford's Rams or 60% like the Titans did last year. Last year the Ram's passed the ball 52% of the time while pounding the rock with Gurley. The Rams have been going downhill in terms of passing attempts since Fisher got here. I believe Goff could put up similar numbers recent rookies if the Rams ran more offensive plays and they pass the ball closer to the average of Fisher's tenure,  55%. This rate seems to be the rate run oriented teams have gotten good performance from rookies (see Winston and Glennon).
Pass  vs Run Attemps (Data form Team's website)      
                  
    Yr    Plays    Passes    Rushes    % Passes
   2010    1019    590           429        58%    Bradford
    2011    958    549            409        57%
    2012    967    557            410        58%
    2013    932    506            426        54%
    2014    910    515            395        57%
    2015    902    473            429        52%    Gurley
                928    513            415        55%    
Fisher’s Avg
    2015    990    535            455        54%    Winston
    2015    922    551            371        60%     Mariota
    2013    934    514            420        55%     Glennon
                 949    533            415        56%     Avg. of the above 3 Rookies