It was just over a week ago when the legendary Tim Duncan, one of the league’s greatest power forwards to ever play, announced his retirement. After spending his entire 19-year career with the Spurs, a career that included five NBA championships and two Most Valuable Player Awards, Duncan was walking away from the game of Basketball.

When the Spurs selected Duncan No. 1 overall in 1997, Gregg Popovich was just finishing his first (shortened) tenure as head coach of the team. Both Duncan and Popovich were heading into their first full NBA seasons in their respective jobs heading into the fall of ’97.

Duncan became a dominant force the moment he first stepped onto the NBA hardwood, averaging 21.1 points and 11.9 rebounds per game as a rookie during that season. The following year, Duncan would be named Finals MVP of the Spurs’ first ever championship team. Alongside him for the celebration, head coach Gregg Popovich.

Three years later, a 6’6″ Argentinian guard with the name of Manu Ginobili joins the roster. Ginobili and Duncan both steadily improved as teammates throughout the first decade of the new millennium, leading the Spurs to an additional three championships (2003, 2004, and 2007). They then went on to defeat Miami in 2014 to win another title, the fifth for Duncan and Popovich and the fourth for Ginobili.

Over the past few years, Tim Duncan and Manu Ginobili served as locker room leaders, making sure other talent such as Kawhi Leonard, Kyle Anderson, and Danny Green work their tails off in practice and in games. Providing assistance and giving advice to the younger guys, Duncan and Ginobili often became coaches themselves on the court in aiding Popovich:

Both Duncan and Ginobili grew close to head coach Gregg Popovich after spending more than 15 years together, and Popovich learned to trust their leadership. When Duncan announced his retirement, it ultimately meant one less locker room leader would be present next season. Popovich immediately realized just how important it was to retain Ginobili.

“Losing Tim made it absolutely imperative that we keep him,” Popovich told Michael Lee of The Vertical. “To lose them both at the same time, it would’ve been like death by a thousands cuts. It would’ve been awful.”

Thankfully for Gregg Popovich and the Spurs, Ginobili ultimately decided to return to the league this summer. San Antonio acted quickly, fending off the interested Philadelphia 76ers and locking up Ginobili on a one-year, $14 million deal.

Both Duncan and Ginobili offer characteristics more advanced than simple on-court results. With Duncan walking away, his leadership, laid back Spurs-like personality, and veteran experience is what Gregg Popovich and the rest of the Spurs will truly miss.

The Spurs still sport a roster filled with veterans — From Paul Gasol to Tony Parker, Manu Ginobili and LaMarcus Aldridge — But the absence of Tim Duncan will truly sting come October.

Gregg Popovich knows that now more than ever before.