Patty Mills is a key piece, but the Spurs' puzzle isn't complete

— -- SAN ANTONIO -- When Spurs point guard Patty Mills agreed early Saturday morning to a four-year, $50 million contract to return to the team, it represented an important first step in free agency for a club prioritizing the re-signing of its own players.

The Spurs brass alluded to the core group's value on numerous occasions after their loss to ?the? Golden State Warriors?in the Western Conference finals.

"We value all the guys that are going to be free agents," Spurs coach Gregg Popovich said earlier in the offseason.

General manager R.C. Buford concurred, when asked about reports of power forward LaMarcus Aldridge seeking an exit from San Antonio.

"We've got a team that's won 128 games [over the past two seasons], went to the conference finals," he said. "We're happy with the group we have. If we can make it better, we'll do it at any opportunity we can. But it's more than just players. It's the fit for our group. Our goals for this team are to continue to compete for championships."

Despite Golden State's dominance -- and the rest of league's ongoing game of catch-up to the Warriors -- the Spurs believed this past season that they had a squad capable of unseating the NBA champions, until ill-timed postseason injuries to point guard Tony Parker and star forward Kawhi Leonard derailed the club's prospects.

So make no mistake, for the Spurs in free agency it's important to bring back a good portion of last year's core group, which captured 61 victories in the season immediately after the departure of franchise stalwart Tim Duncan, securing back-to-back 60-plus-win seasons for the first time in club history. That's why San Antonio prioritized re-signing Mills.

Mills was expected to fetch in the neighborhood of $12 million to $15 million on the market, but he signed a team-friendly deal that leaves San Antonio approximately $13.3 million in cap space, provided it renounces the rights to all its free agents outside of restricted free agent Jonathon Simmons.

It's true, the Spurs did shop Aldridge and Danny Green as potential trades prior to the NBA draft, according to multiple sources, but they found no takers in their attempt to create more cap room. Perhaps San Antonio is still interested in moving them.

But the next order of business now is to try to lure back Simmons -- a restricted free agent who already has garnered interest from several teams -- as well as finding that "fit for our group" that Buford described. The Spurs were expected to meet with Golden State free agent Andre Iguodala in Los Angeles, according to ESPN's Chris Haynes. And they've touched base with representatives for the? Sacramento Kings'? Rudy Gay, per sources, although a signing isn't imminent.

The Spurs already tendered a qualifying offer to Simmons, a homegrown talent, and because he's a restricted free agent, the team has a right to match any offer he receives -- something it won't do if competing offers get out of hand. A source confirmed the Spurs are working on an offer that would pay Simmons annually in the $9 million range.

Obviously, Mills' signing doesn't completely address the issue at point guard, given that Parker's recovery from a ruptured left quadriceps tendon is expected to stretch into 2018. But that's what made bringing back Mills even more important. Without Mills, the rehabbing Parker and Dejounte Murray, coming off his rookie season, would have been the only players at the position on the roster with NBA experience.

Having played the past six seasons in San Antonio, Mills is one of the team's most impactful bench scorers. He is ingrained in the club's culture, knows the system and Popovich's way. Perhaps Mills gave the Spurs somewhat of a discount, considering he received significant interest from the Brooklyn Nets, according to ESPN's Adrian Wojnarowski. But his new $12.5 million average salary represents quite the raise from the $3.57 million Mills earned in 2016-17.

Mills also provides a proven veteran presence at point guard. He is capable of taking over as the starter as Parker recovers. And he will help to groom Murray for the starring role San Antonio envisions the rising second-year man taking in the future.

The Spurs might still address the point guard position. They've shown interest, according to sources, in bringing back Utah's George Hill, who spent the first three years of his career in San Antonio before leaving in the trade that brought Leonard into the fold. A Hill signing doesn't appear too imminent, however, as he has garnered interest from multiple teams that could push his value beyond what San Antonio is willing to pay.

Then there's the matter of whether Manu Ginobili plans to play next season or retire. And how much Pau Gasol is willing to take in a long-term deal the sides will soon begin to craft. And finding potential depth to replace players such as Dewayne Dedmon and David Lee, who both opted out of the final years of their deals. But multiple sources indicate the club isn't expecting to deviate from its typical low-key approach in free agency.

"We don't have time to go through the decision-making process now because that's pretty complicated," Popovich said after the season. "It depends on a lot of factors."

Luckily for the Spurs, bringing back Mills is no longer one of them.