Depending on the past few days of training he maybe technically fit, but he certainly wont be match fit. The only way to get that is to play games, starting with Newcastle.
I doubt very much Gus will start with him, as players will be fresh and Vicente may try too hard to adapt to an early games pace etc. So i guess Gus will put Vicente on for the last 30-20 mins or so, just to ease him in and them ramp it up over te next few weeks. Much like last year.