Nothing wrong at all.
In fact, very useful.
What type of impression would a team create for their rookies if they just strutted in and were handed a place on the roster? How much would that motivate them to improve and compete to their fullest ability?
Get the rookies into camp and introduce them to the veterans that will play their position if they don't impress enough.
I guarantee that you will then see a different level of motivation than you would without these low-cost veteran free agents.
And who really knows? That veteran, who probably feels somewhat disrespected at this point, may just develop a new competitive drive that leads to an unexpected breakout. It has happened.