Sox diagnosed Napoli with avascular necrosis
Mike Napoli - C - Boston Red Sox
Jan. 22, 2013 - 5:00 PM ET
Mike Napoli was diagnosed with avascular necrosis during his pre-signing physical with the Red Sox.
It's a disease brought on by poor blood supply that can kill cells in bone tissue. Napoli doesn't have any symptoms currently and should be fine going forward, but the discovery that he has AVN is what prompted to the Red Sox to restructure his contract from a three-year, $39 million deal to a one-year, $5 million deal. Bo Jackson and Brett Favre both played through avascular necrosis.
Source: Pete Abraham on Twitter