NBA referee Greg Willard, who was scheduled to work last Wednesday's playoff game between the Spurs and Thunder before being replaced because of illness, has been diagnosed with pancreatic cancer, ESPN.com reported Monday.

Referees during the NBA Finals will wear No. 57, Willard's number, on their shirts during games in his honor, the NBA Referee Association told ESPN.com.

Willard worked a number of playoff games this season, his most recent being a game between the Heat and Celtics last week.

Willard has been an NBA referee for 24 years and has worked the NBA Finals since the 2009-10 season.