Not a problem, it’ll be fine. Just remember 1/4" stereo headphone output to 1/4" balanced mono input!
So if you put a normal signal lead (unbal) into the headphone socket all the way, it’ll short out one side of the headphone amp!
It’s alright to put an unbal 1/4 into the soundcards input it’ll just unbalance it.
You can bodge the headphone plug by not putting it all the way in into the socket, so the tip only engages the first indent, thus tapping only one side without shorting the other.
Otherwise you would need to wire a suitable jack using a stereo plug wired for one side of the headphone output to a mono (unbal) jack for the pre input.