In the long term, the most important free agent for San Antonio, even more so than Tim Duncan, is Kawhi Leonard. He's restricted, meaning that the Spurs will have the opportunity to match whatever offers he receives. Leonard is widely expected to get the max, and the Spurs can offer a fifth year on his deal whereas he can only get four years from someone else. It's theoretically possible that Leonard can take just a one-year qualifying offer so that he can hold out for a higher max contract when the salary cap expands next season, but that'd be a bit of a gamble and by all indications he's happy with the Spurs. I doubt he'll even draw serious attention elsewhere because everyone knows the Spurs will match anyway. Prospective suitors can't make him sign an offer sheet to mess with Spurs cap room, like what happened with Chandler Parsons last summer between Dallas and Houston. In all likelihood Leonard will sign late in the summer, after the team has made all of their other moves, and they'll use his Bird rights to go over the cap to retain him.
This exercise, then, is to find someone to back up Leonard, or perhaps to play alongside him in small-ball lineups that are becoming more and more prevalent in the NBA.
As you're likely well aware, Marco Belinelli is among the litany of Spurs free agents and though he's a valuable three-point shooter, his poor defense and limited athleticism leads one to wonder if San Antonio can replace him with someone who's a better fit. That Belinelli also figures to draw a hefty raise in pay from somebody just increases the odds of him moving on from the Spurs, though you can read more about the pros and cons of keeping him here, in part of a series of "Should he stay or should he go" debates J. Gomez and I had about Spurs free agents.
Here are four guys who might fit for the Spurs, not only with their skill sets but also with the team's culture in general. All salary information is via Hoopshype.com. You'll forgive me if I don't include LeBron James or Draymond Green as "realistic free agent targets." We're looking for guys who'd be okay with a backup role, here.
Last Team: Bulls
2014-15 Salary: $3,000,000
Dunleavy has been a starter for the majority of his career, but he is going to turn 35 before the next season starts and might be willing to accept a reserve role for the right team and the right situation, especially since he's still looking for that elusive championship ring. He started the last two seasons in Chicago and shot 40.7 percent from downtown, and his percentages have been in that neighborhood the past five years.
The former "Dookie" has been a solid but unspectacular defender throughout his career (career -0.1 Defensive Box Score Plus/Minus) and also contributes on the glass. He's not much of a playmaker, but does understand the "pass up good for great" philosophy the Spurs use. He's also got a sneaky dirty streak to him, which became a story late in the first round of the playoffs against Milwaukee.
If you don't think Pop likes guys who'll throw a stray fist now and then, you haven't been paying attention. Two prominent role players during the Duncan/Popovich Era were Bruce Bowen and Robert Horry, and even Manu Ginobili has made a career of driving to the basket with his lead knee up and his elbows out. You can't win in the NBA with a team of choir boys.
Dunleavy is a bit long in the tooth, but a short-term deal might make sense for both sides.
Last Team: Kings
2014-15 Salary: $1,063,384
Hey, the age surprised me, too. It feels like Casspi's been in the league awhile, but he's just entering his prime after struggling with injuries the past couple of years. He rejuvenated his career last season with the Kings, shooting a career-high 48.9 percent and 40.2 from three. He probably won't shoot quite that well again, but Casspi is 6'9, skilled enough to drive to the basket and is a good rebounder when motivated. His defensive work has never matched his athleticism, but perhaps the Spurs can draw more effort out of him in that regard. Casspi is definitely going to get a decent contract from somebody, and I'd be very interested in him for the mid-level exception.
Last Team: Rockets
2014-15 Salary: $4,702,500
Brewer is the best defender of the bunch, a spastic, non-stop bundle of energy who specializes in filling the wings in transition and beating opponents down the floor for easy points. He's mostly a horrid shooter -- career 29 percent from deep -- but he's also one of the streakiest in the league, and gets insanely hot on occasion. Brewer's appeal is that he never has to be told to play hard, he's versatile enough to guard point guards and he's been pretty durable throughout his career despite his lithe frame. He's been a reserve for most of his career and by now mostly knows what his strengths and weaknesses are and stays in his lane. Brewer does, at times, do boneheaded things down the stretch of games, but he's an asset for a contender as long as they don't look to him for offense and don't play him too many minutes. It remains to be seen if his price tag will be too prohibitive.
Last Team: Clippers
2014-15 Salary: $3,250,000
Delfino has lost the past two years trying to recover from a career-threatening foot injury, but he claims he's finally recovered enough to give the NBA one more chance and the Spurs, offering perhaps a chance to play with his countryman Ginobili, could be the ideal landing spot for him, with a one-year make-good contract. Before his feet betrayed him, the Argentine swingman was someone who could get to the rim and finish and also a capable three-point shooter. He's never been much of a defender, but he did flash an edge now and again. As long as both the salary and expectations are low, Delfino could be a free agent bargain, provided he truly is healthy and looking to prove that he can still play.
There are a few other guys out there, but they're either restricted like Mirza Teletovic and Kyle Singler, or happy in their current clubs like Al-Farouq Aminu and Jared Dudley, or both like Jae Crowder and Joe Ingles. Either that or they're complete non-shooters, such as Alonzo Gee or Lance Thomas.
It's all probably moot anyway and PATFO might just feel that Leonard's backup is already in-house and that their resources are best used elsewhere. I'd agree with the latter part of that statement, at least.