Here is what I think is a Chicago Cubs BP Cap from 2017.    The New Era 59Fifty is the official MLB Cap provider.  The hat has a White C with red outline.   The right side of the cap has the NL logo embossed on it.  The cap has number 2 written into the cap which would have been readied for Tommy LaStella in 2017.   The cap is a size 7 1/8.   The hat does not show any use so I believe this was readied for Tommy but not worn. 

The cap is authenticated by MLB as team issued.  The Cubs did a mass authentication of caps from many years prior to the 2023 season and did not document whose caps they were.

Happy to answer any questions.