A couple of things;
1. Saw Mike Lombardi on McAfee show. He showed a graphic on the percentage of First Round picks by position that are successful (I missed the measure of "successful", may have been "signed to a second contract") O-Line had the highest percentage of success. They are the safest pick.
2. My experience with athletes and knee injuries is that they don't fully regain their athleticism until 2 years removed from it. No reason to think that Morgan won't get better.