We know the 49ers value the position highly. They've devoted a roster spot and quite a bit of money to Jennings for years. Now he's 36 and they bring in the consensus best long snapper in college football.
I can't think of a way they hand the keys to a rookie at such a high-pressure, specialty position when we have Jennings in place still playing at a high level and we aren't desperate for the cap space. But I also can't think of a way you waste a practice squad spot on a long snapper.
So what's the protocol here? Is there anyway to "develop" McDermott without wasting a spot on a nearly worthless player?