Xen is limping on his front right leg. I have checked his paw, their is nothing un-toward there, his leg doesn't look swollen or anything, however the limp is quite noticable when he walks, gets up from lying down. The only thing I can think it is, when we were playing with his ball on the field today, as he tried to grab his ball he tripped and did a roly-poly, do you think he's pulled a ligament or something? How long shall I give it, to see an improvement before contacting the vets? I have been trying to keep him calm etc since, we haven't been on our 2nd walk tonight because of this, however keeping a 9 mth old shepherd calm isn't easy