Not a huge deal to me, probably just unwinding. If the story was...Pierce hammered at a club at 4am, we have a problem.
A couple drinks, a liitle poker for some distraction is probably a good thing in my mind. Get your mind off things, come back ready. It's like any job.
Also, Pierce is what 6' 7" and 235? I doubt two glasses of win even affects him much at all.