Probably meaningless, probably dumb, but he'll wear #11. Stowers came up and got 83, Diaz got 84, Vavra got 77, Ortiz got 65. Stowers and Vavra have since changed so probably didn't want those numbers. Adley, Gunnar, Grayson got more standard numbers. Kinda seems like they think of him more in the latter group.
I think there's definitely something to be said for this phenomenon. The long-shots who get the call aren't given the lower numbers simply because they need to overcome greater odds of sticking with the club. Or, they're just temporary injury replacements anyway.
The fact Westburg was given #11 suggests what we already knew about him.