At no position is college football's 20-hour practice week rule more impact full than at tight end. When you consider the role these guys would ideally fill in the passing game, which is often all that a WR is asked to master, plus the role they fill in the run game which is comparable to what the OL has to know, it's easy to see why this is an impossible task for most players.
That's before you factor in the needed mentality and skill set needed to master the arts of blocking and receiving. One requires aggression and a desire to seek out contact, the other is all about avoiding other players. The best blockers have heavy violent hands while receivers need soft hands. The best blocking TE dreams of pancaking an opponent and works to make it happen, the best receiving TE dreams of bringing in a TD catch by out-leaping an athletic safety in the end zone.
These skills can overlap, but they frequently don't, and the 20-hour rule means one is generally going to be more developed at the expense of the other.
Everyone loves hybrids but you set yourself up for trouble if your offensive system depends on always having one at a particular position. That's why coaches have means of protecting the star receiving TE from onerous blocking duties when they happen to get their hands on one. Here's a few of the tactics that can allow that protection to happen.
Tactic 1: Don't rely on them at the point of attack
If you watch a team that lines up in 11 or 20 personnel with a receiving TE on the field in-line or in the H-back position long enough you'll notice that they never seem to play a crucial role in the success of a running play. Instead the offense will do things like run the ball to the "weakside" of the formation as that's not actually where they have the greater chance of success.
Here's an example, inside zone blocking but with the TE just aiming to preserve the edge while the RB is aiming A-gap to cutback:
In a play like this one, the RT can help the TE double team the DE before moving on to the 2nd level and then it's just on the TE to screen that defender. He doesn't have to try to drive him off the ball or decisively "win" his block, he just needs to avoid losing.
There are ways to block various running plays that can remove the burden for the TE of winning the point of attack for the offense. In those instances, he can just be adequate rather than legitimately good.
Teams that feature a receiving TE will also bring a FB or additional TE to the field when they want to run the football and either take the receiving TE out or give him an easier task while the blocking specialist is asked to go win the point of attack. For instance on power:
In this instance the TE is advancing to take out a LB with some momentum rather than being asked to win the point of attack against a DL, that duty instead falls to the extra TE/FB that's been brought out onto the field.
Go watch a power or otherwise physical running team that utilizes a famous receiving TE and take note of how often they're actually asked to make the crucial blocks.
Tactic 2: Protect them with the option
There are two ways teams will go about doing this, the former of which is becoming less popular than the latter but we'll start there anyways.
In the spread-option offense where the QB is regularly used in the running game there's really no pressing need to ask the TE to take on particularly difficult blocking assignments on the edge because those DEs can just be optioned off anyways.
So on zone-read, the TE can loop around and pick off a LB or DB as a lead blocker for the QB:
And he can do the same on power-read plays:
That's still a blocking role of some importance but it's consistent across both schemes and it's one that a receiving TE can more easily approach than executing a kick-out or a base block on a DE.
The problems with this approach are easy enough to see, these schemes rely on a running QB and they still ask the TE to be an important part of the blocking plan. Stalking linebackers in open grass should be within the means of most TEs but the techniques still take time and these schemes are often at their best when paired with traditional zone and power schemes where the TE is again doing yeoman's work at the point of attack.
The rise of the second option is why we're now seeing a huge rise in "pro-style spread" offenses. The second option is to send the TE on a route as part of an RPO (run/pass option). If you have a TE that's excellent running quick routes as a part of a West Coast, drop-back passing game then why not have him run quick routes while your OL is blocking for a run?
In this example the TE is just settling into open grass behind the middle linebacker, unless that defender doesn't want to help stop the outside zone run by the offense. The QB reads the linebacker to determine whether to hand-off or throw. If he's fooled, he's still got a nice curl-flat action to the field he can turn to.
With RPOs, receiving TEs can have a tremendous impact in boosting the running game but by doing what they do best which is presenting a match-up problem in the passing game that requires extra attention. It's somewhat curious that Alabama hasn't really figured this out with O.J. Howard yet but they've managed to get him executing slice blocks on inside zone at a fairly high level so we can forgive this oversight. They do this some but not as much as they could given his prodigious talent, perhaps that'll be a feature in 2016.
Division of labor has always tended to bring the best results unless you have a true hybrid that is legitimately great in multiple roles. Most tight ends are not legit in multiple roles and need to be shielded or set free to focus on what they do best. These approaches define most of the common approaches for protecting match-up nightmare TEs that aren't also great blockers.