That Rivera is not only building this team with talent, but also, and more importantly, he is building a culture.
It is a culture that values hard-work, opportunity, and putting the team first.
Look at two players that signify this.
First, Jeff Otah, an extremely talented player, who has the potential to be a top 5 RT in this league. However, over time, it has become apparent that Otah did not have the work ethic or desire to come back from injuries, or to play through negligible amounts of pain.
Next, look at Thomas Davis, who is also an extremely talented player, who had/has top 5 LB talent. However, as apparent as Otah's lack of desire was, Davis' was desire and hard-work was obvious to anyone.
These moves illustrate that if even if you are 'injury prone', if you bust your ass, be a team player, and not make excuses then you will have the opportunity to prove yourself.
Word of advice to new players, if you haven't already noticed, bust your ass and work to get better, than you can unseat a first round draft pick even if you are an undrafted rookie. (Byron Bell).
This is how winning cultures are built.