San Antonio Spurs center Tim Duncan has elected to exercise the $5.6 million player option on his 2016-17 contract – but that is not an indication he’ll return for his 20th NBA season, league sources told The Vertical.

Duncan, 40, is still seriously contemplating his desire to continue playing, as well as judging how his body feels, league sources said. The Spurs are allowing Duncan to make a decision on his own timetable, but there’s no question that this offseason is the most seriously he’s considered retirement.

Duncan – a five-time NBA champion, three-time NBA Finals MVP and two-time regular season MVP – could take his decision into the start of July free agency.

Duncan’s productivity declined this past season when he averaged 8.6 points and 7.3 rebounds. He’s averaged 19 points and 10.8 rebounds for his career.

The Spurs lost to the Oklahoma City Thunder in six games in the Western Conference semifinals.