Photo by Adam Hagy/NBAE via Getty Images Nelson Jr. joins the Spurs after suiting up for them in the Summer League. The San Antonio Spurs have filled their final roster spot before training camp begins next week. According to the team’s roster web site, the Spurs have signed undrafted rookie Jameer Nelson Jr. to a training camp contract. Nelson Jr. played with the Spurs in the summer league, where he averaged 4.1 points, 1.3 assists and 0.6 turnovers and shot 27% from deep in 11.2 minutes per game. He primarily came off the bench and was the team’s third point guard behind Stephon Castle and Jamaree Boyea. The 6-foot-1 guard played five years of college basketball, finishing out his career with TCU where he averaged 11.2 points, 3.3 assists and 2.1 steals. He is the son of former NBA guard Jameer Nelson. Nelson Jr. is the 21st player signed to the Spurs training camp roster. The team can have just 21 players on the training camp roster, meaning they cannot invite anymore players. San Antonio has four training camp invitees without a spot on the NBA roster: Riley Minix, Brandon Boston Jr., Malachi Flynn and Nelson Jr. With a Two-Way roster spot open, it’s likely these players will compete for the final roster spot. The training camp contract likely means that even if Nelson Jr. doesn’t make the final roster, he will spend some time with the Austin Spurs in the G League this season. San Antonio has used this strategy in the past to keep undrafted rookies in their system without having them on the NBA squad. San Antonio will host a media day on October 1st, then begin training camp the following day. They’ll play their first preseason game on October 7th against the Oklahoma City Thunder.