Spies was forced off the field when he coughed up blood last August, and was sidelined for six months after being diagnosed with a pulmonary embolism.
The 22-year-old was given the all-clear last Friday and allowed to travel to New Zealand to join his team-mates.
"He is extremely valuable to us. With the new laws in the modern game I'm sure that they will suit him perfectly," Ludeke told the Pretoria News.
"He will be crucial in getting us vital line breaks to put opposition defences under pressure. We will make a decision about him in the course of the week but he will definitely be playing whether he starts or comes off the bench."
The Bulls, who have lost four of their six games this season, will also welcome back full-back Zane Kirchner from a two-week suspension as well as Springbok winger Bryan Habana from injury.