Yes, they are allowed on leash. Also, there is a dog park at the east end of Valley Mission Park if you would like to go off leash.
Rebel is spot on. Ive taken my GSP of leash when the park is not so busy and let her sprint in the back.
As long as they are on a leash. Park is pretty big though, so you could probably get away with finding a corner to let Spot off his/her leash to play fetch.
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