Massage. You can do it yourself. "Trigger Point Therapy Workbook" by Clair Davies is a body saver.
I've been using Trigger Point Therapy, and this workbook, for years. It has done wonders for most myofascial-related pain, however, even with using trigger point therapy, it still took a solid 2 months for the tennis elbow to completely subside. I think the reason may be that trigger point therapy is excellent for muscle pain, as muscles get much better blood flow than tendons do. Since tennis elbow is tendon pain, I think he is in for two months of not playing bass.