Extra Pipe Off Shower Stem

I have an older home and am remodeling the bathroom. I want to change the tub/shower faucet, valve and head. After opening the wall I noticed a T coming off the shower head stem with a pipe going down through the floor. I have the ceiling out of the room under it and noticed that the 1/2" copper pipe has a 1/4" pipe ran into it, hammered tight and then soldered. The 1/4" pipe then disappears into the wall where the main plumbing stack and piping are. I would like to know what that pipe is for and if i can remove/cap it to install the new shower valve and stem. I have attached a picture showing the old valve and where the pipe comes off.

Thanks

It could be someones idea of a trap primer for a drain.

Like Jerome says, it's most likely a primer for a near by floor drain. We've done the same thing whenever there's no laundry sink. You should try to re-install it with the new setup.

Great,

There is a laundry room with a floor drain underneath. Thanks for the quick and helpful replies.