dont want my Chihuahua mix to run if i take him off the leash

Question
I just aquired a wonderful dog (This is my second question about him) Who
was
just let out of the house by my a jerk of a neighbor and was running around
the
neighborhood when i was moving in and came right up to my apt. We are
now best
friends and i live near a school and want to let him run free and play fetch in
the
baseball field but there are openings in the fence and dont want him to run
out and
get hit by a car. He loves to run and we run while he is on a leash. How can I
train
him not to just jet when he can. Thanks!

Answer
Do NOT allow that dog off leash!!!!!!

This dog has been "free" and became accustomed to sniffing, following scent trail, chasing birds, etc. and HE WILL RUN.  A solid recall (Come when called) takes months (not weeks) of training, and even then there are dogs that cannot be trusted off leash.  These are scent hounds, sight hounds, dogs with strong triggers (visual) acquired by being free, dogs with high prey drive, etc.  Even the BEST TRAINED dog (AKC obedience titles) cannot always be trusted to recall.  DO NOT take a chance.  I will teach you how to train your dog to recall but I STRONGLY advise you NOT TO TEST THIS DOG.  Find another venue where he can run free (like a dog park, or securely fenced area).  All he has to do is FAIL ONCE in order to be irretrievably lost or killed.

The recall can be easily conditioned (for emergency use ONLY).  Buy a whistle (police whistle).  INDOORS ONLY, walk toward the dog with a treat in your hand.  The dog will back up as you approach (and you must approach slowly) and will eventually sit (when a dog looks up, as you hold the treat over his nose, he will automatically sit.)  The SECOND HE SITS, blow the whistle (VERY LIGHTLY) and pop a VERY GOOD TREAT into his mouth (piece of hot dog, smelly cheese, steak, etc.), then praise him and leave it at that.  Repeat this very randomly two or three times the first day and every day thereafter for approximately two weeks.  The dog will acquire a strong conditioned response: he will be SEATED VOLUNTARILY IN FRONT OF YOU at the SOUND of the whistle for EXCELLENT FOOD REWARD.  This is a "picture" in the dog's mind: whistle, seated, reward/praise.  Once the dog is obviously conditioned (and you will know this), start blowing the whistle (a little harder and louder) from a few feet away INDOORS ONLY.  The dog SHOULD come to you, sit, for food reward.  The first time he does this, put your hand to his collar (gently and casually), grasping it, BEFORE giving him the food reward.  Repeat this randomly several times a day (don't overdo it) for a few days, and then start leaving the room and blowing the whistle from another room.  You should be able to progress to the point where your dog will LOOK FOR YOU IN YOUR HOME in order to sit (your hand to his collar) for JACKPOT (large handful) of food treat/praise.  You now have a solid EMERGENCY RECALL (but you must randomly play this "game" indoors a few times a week for quite a long time.)  THIS DOES NOT MEAN this recall can defeat the self rewarding behavior of chasing a squirrel, a cat, a bird, or following scent.  Protect the dog; don't allow him off leash in any area he can escape from.