So if Riley was a horse I would describe this as him being off in his left fore/front and is head bobbing lame.... For everyone else, Riley is limping on his front left leg/paw and is limping enough that he is bobbing his head ever step, but is not three legged lame. I have no clue what he did. We did go to the dog park Fri-Sun, complete with swimming (kinda) and lots of playing/ball chasing, so it is possible he did it there, although it did not present until this (Mon) morning. He also was in a reactive fit mode Sunday night and ran into the concrete front porch while barking/lunging at a person bringing out their trash (very dark at the time). OR he could be showing symptoms of Lyme,since he was bit by 3 ticks about 6 weeks ago. He's only very noticeably lame when walking on pavement and it seemed subtler this morning, and then worse later but it has not gotten any worse since around noon today. He's already on for a vet apt this Wednesday for his annual, so I think it may be ok to wait until then since it's one day. I dont know what to think... Lyme? A sprain? Bruise? I dont believe it is a break since there is not any range of motion issues or obvious pain when I manipulate his leg/joints. Any ideas or suggestions?