Brett Favre's painful shoulder appears to be related to a partial tear of the biceps tendon.  Which is certainly good news for #4.

This type of injury presents many options; none of which require major 'open' surgery. Rest and rehab or arthroscopic surgery and rehab are the two most likely courses; with arthroscopy being the speedier path.  In all honesty, the biceps tendon will probably completely rupture and end his pain naturally.

This injury should be a minor factor in the annual 'will Brett return for next season' saga. 

Whichever course that he ultimately chooses after the pain resolves, he should not have any significant loss of velocity. 

Now let the speculation madness begin.