Two things your guinea pig won’t need are an exercise wheel or an exercise ball. Although both of these toys are popular for hamsters and mice, the anatomy of your guinea pig makes it very difficult for him to use either item safely.
If you purchase one for your pet, he will just sit in it and will likely look uncomfortable. A guinea pig’s spine is not flexible enough to curve into a comfortable position to run in a ball or on a wheel.
In addition to possible spinal damage, he can injure his feet, ankles, or legs, so it’s best to leave these toys to pes that can use them and enjoy them