Newly signed Boston Red Sox first baseman Mike Napoli said he never has experienced symptoms from a very serious hip condition known as avascular necrosis, which he says was diagnosed during the physical he took for the team last month.

The condition, known as AVN, restricts blood flow to the hip joints and can ultimately collapse the bone. It is what ended the athletic career of two-sport star Bo Jackson.

Napoli, 31, said the condition, which is in its earliest stage, should not affect his ability to be Boston’s first baseman for 2013.

In a conference call Tuesday to announce that he finally had signed with Sox — getting a one-year deal — Napoli said he first learned of the condition after taking an MRI with the Red Sox in December, shortly after he and the team agreed on a three-year, $39 million contract Dec. 3.

Since then the Red Sox and Napoli’s agent, Brian Grieper, have been working on a revised deal, gathering medical opinions from several doctors. They finally came to terms on a oneyear contract for $5 million that includes an $8 million incentive package Napoli can earn if he stays healthy.

Napoli has played 133 of his 727 major league games at first base.

Napoli loves hitting at Fenway Park, where in 19 career games he has batted .306 with seven home runs, 17 RBIs, a .710 slugging percentage and a 1.107 OPS.