For years, some N.F.L. teams didn't wear numbers on their practice jerseys in order to thwart the possibility of spies.

Meanwhile batting practice jerseys are worn during home and road batting practice, as well as during select games throughout the year.

Each professional football player is usually equipped with a set of practice jerseys as well as four game jerseys.

(The NFL had previously allowed teams to sell ad space on the practice jerseys in 2009.)

The team wears short-sleeve practice jerseys with the word Dominicana sewn on the chest.

Beginning in 2007, the Dolphins' practice jerseys now have last names on the back.

In 2008, the league allowed sponsors on the practice jerseys of the uniforms, but not the game-worn uniforms.

Some of the players still had their practice jerseys on, some had started to change to their game uniforms.

Must be a slow news day, who cares that they taped a C to their practice jerseys?

The Blackshirt tradition began in the 1960's, when two of Bob Devaney's assistant coaches went to a sporting goods store to buy practice jerseys.