In the course of the English language’s evolution, many words were shortened or changed as a matter of regional dialect, or simple convenience. It happened with names, too.
The name Staley came about that way. Originally, it was Stallard. Either as an example of friendship or kinship, the name was altered – for example, a young brother might call his older sister Vivian – Vivi – because of the difficulty. Later, the entire family might call the sister Beebee, because that’s how the baby brother sounded it.
It was the same with Stallard, which became Staley – for whatever reason.
Stallard is an English nickname or byname that was originally used in medieval times to describe a valiant or resolute person, from a reduced pronunciation of the Middle English word stalward or stalworth = ‘stalwart’ (an Old English compound of stael ‘place’ + wierðe ‘worthy’).
A. E. Staley was an Illinois businessman whose factory workers played football after the quitting-time whistle sounded. They were called the Decatur Staleys, to honor their boss. The team later was renamed the Chicago Bears, and their mascot bears the title of its namesake team founder, Staley the Bear.