John Lynch and Kyle Shanahan were plenty active during free agency, and many of the roster additions were players familiar with the coaching staff and the systems they are implementing. The most notable on offense are guys like Brian Hoyer and Pierre Garçon, but Tim Hightower is worth a mention as well.
Hightower played in Washington when Kyle Shanahan was the offensive coordinator. Washington acquired Hightower in a trade shortly before 2011 training camp. In five games, he rushed 84 times for 321 yards, before suffering a torn ACL. The injury was a brutal one and Hightower ended up needing another surgery.