Generally a male puppy's testicles drop around 6 or 7 weeks, however it can take up to 3 months or longer in some instances.
When you say he was purchased for breeding do you have some kind of contract from the breeder & does this mean he was purchased as a show prospect?
Also at 14 weeks old there is no real way of telling whether or not he will be up to breeding standard. At any rate he shouldn't be bred from until he is sufficiently mature enough to have the recommended health testing performed.
When a dog only has one decended, or in fact if neither have dropped for that matter he is suffering from what is called Cryptorchidism, or retained testicles which is considered a genetic trait & dogs who have a retained testicle(s) should not be bred from.
Another point to consider is that a dog with retained testicle(s) has a higher chance of testicular cancer & therefore should be neutered.
Here's a link on Cryptorchidism FYI