The NFL has a policy whereby if a rookie has not yet graduated from college, they are not allowed to participate in Organised Team Activities (OTAs).
This only affects certain players each year, such as Oregon State University's Markus Wheaton last season. He was drafted in the third round by the Steelers, but missed all of OTAs, something which undoubtedly stunted his growth and development during his rookie season.
This year the Steelers 6th round pick, linebacker Jordan Zumwalt, suffered the same problem as Markus Wheaton did one year ago, he was forced to sit out the Steelers OTAs because his class at UCLA had not yet graduated.
If anything, the situation has been worse for Zumwalt this year. Wheaton, a third round pick, was a virtual lock for a roster spot. Zumwalt has no such early draft choice protection, and will be up against what promises to be some very fierce competition at the linebacker spot during training camp.
Whilst he was unable to attend OTAs, he was still allowed to contact coaches and assistants whenever he wished, as well as consume as much of the playbook as he was able. Per Mark Kaboly of the Pittsburgh Tribune, Zumwalt made the most of that opportunity.
However, no matter how much he worked on learning his playbook, and no matter how much he conversed with the coaches, he was still at a disadvantage compared to the other rookies and players who attended OTAs.