That players historically dont improve their ability to play football when they lack conditioning and coaching. In fact, it almost always goes in the opposite direction. For example: Mike Wallace held out last offseason for the Steelers. Despite returning before he missed any real games, he dealt with nagging injuries and his production dropped.
You seem to be suggesting that every holdout will result like our past situation. I disagree, i think its counterproductive to this team if our players miss practice. Even if they end up like Tannehill and perform admirably, i seriously doubt they did well
because of their holdout.
edit: and because you asked, another example of skipping practice but playing in games:
http://espn.go.com/blog/nflnation/post/_/id/60748/darrelle-revis-injury-a-repeat-of-2010
There are many more.