hours cut due to 'day to day effort' but no prior warning

Location: Boston, MA

Hi there I work in a service/retail job and my boss just told me he was cutting two of my three 8 hour work days there, while my other coworker mantains their four days. When I pressed as to why, he explained it was due to 'day to say effort' but there had been no prior discussions about any effort issues on my part.

This was all over text and I am just wondering if this counts as something I could legally pursue as some sort of retaliation.

Thanks guys