The NBA trade machine could get cranked up Friday, the first day free agents who were signed over the summer can be traded. But don’t expect the Suns to do a lot of wheeling and dealing. General Manager Ryan McDonough said that while Phoenix will look for ways to upgrade its roster, its focus is on doing that internally as players return from injuries. The Suns are hopeful Devin Booker (strained left adductor muscle) will be back for the Dec. 26 game against Memphis and that rookie shooting guard Davon Reed (offseason knee surgery) will return around Jan. 1. Center Alan Williams, who had surgery in August to repair a torn meniscus, could be back sometime in March. “If we do make a move it will be positionally to fill a short-term need,” McDonough said. “There’s nobody we can sign or trade for that’s going to come close to replicating half of Devin Booker’s production. Nobody out there is 22 years old and like Davon Reed, who we’re really high on. So we’re most excited about getting those guys back.” The Suns could clear a logjam by trading one of their three centers but that’s easier said than done. Alex Len can’t be traded until Dec. 23, three months after he signed his qualifying offer.