My T was a hard no on gifts but ALWAYS accepted cards. I think in general most will. I even gave him one this year and included a gift tag in it (because it was a theme for the card) and he was like "is this a bookmark?" and when I said no, he was like "Well it's gonna be now" and I put in a collage of photos of our adventures that I printed and he loved it.

If you are worried, do what I did last year, just leave it on his desk as you walk out