Well, a 14 week old puppy has the bladder capacity to hold it 8 hours or more. It's just the training that will be needed.
Stay consistent with your training and you should do good.
I had a litter of Lab puppies (only 4 this past time). With this litter, with it being smaller (we lost 3)...I decided to work on potty training while they were still here. In the whelping pen, I put down wee-pads in the corner of their pen and they naturally starting going on them at 5 weeks old. There's an attractant in there that'll encourage them to use that area. Some didn't quite make it on the pad at that age, but they were in the area.
By the time they left, they were going in one spot and it made clean up a breeze. With the pads, it's very easy to train. You can even litter train your puppy too...
I would start out with the pan, and put the wee pad in it. Don't add the dog litter yet, just get puppy to potty on the pad, inside the box first. Then gradually add litter in ontop of the wee-pad, and then eventually add more and more litter, then take the pad away. Works like a charm!
With a dog that small too, you could always get a larger pen, and place the litter box in the cage, incase he/she has to go, it's right there. Or maybe a little "round pen/play pen" area if you don't want to use a crate.