Single golf club on a plane

I'm currently in the USA and have seen the putter I want at a ridiculous price.

However, I have not got a golf bag with me to put it in on the way back to the UK. So my question is, can you bring a single club back as extra hand luggage, or as an extra suitcase?

If it helps, I am flying with Delta, but the hotel PC is so bad I cannot load their page!