The 24-year-old was the bolter among the 25-man squad named for the team's camp in Palmerston North next month.
A former Otago and Dodgers pitcher, Watts now plies his trade in Christchurch.
In March he pitched Papanui to the final of the national open club tournament.
Wellington's Zac Boyd was included after a strong showing in February's Black Sox trial.
Harrison Valk was also included after an impressive performance at the under-19 world championships with the Junior Black Sox.
The 17 players that won the Intercontinental Cup in Prague earlier this month were included, as were familiar names Nathan Nukunuku, Wayne Laulu, Tyrone Bartorillo, Josh Harbrow and Josh Pettett.
''The 17 players who toured this year laid down a marker for what is required next year, but we are also excited about welcoming back some of our veteran players, and the competition for places that this will generate,'' head coach Mark Sorenson said.
''There are still a number of spots up for grabs in the World Cup squad and this camp represents the first step in making this team.
''We are also excited about taking part in a number of activities organised by Manawatu Softball, who have been a great support in putting together this weekend.''
