Serge Ibaka quietly signed a 4-year, $48 million extension with the Thunder over the weekend. August and September are the slowest months of the year for the NBA, so the news went largely unnoticed at a time when everyone is conducting fantasy football drafts or devouring NFL preseason football games. (Or, spending the final few days of summer on the beach.)

One person definitely noticed the extension: James Harden.

Here’s why – check out this snapshot of the Thunder salaries for the upcoming years: [Note: Russell Westbrook's 5-year, $80 million extension is done, but his yearly salary numbers aren't available yet, so $16 mil per is an estimate.]

$17,548,838
$18,773,176
$19,997,513
$21,221,850
$0
$16,000,000$16,000,000$16,000,000$16,000,000$16,000,000
$7,800,531
$8,477,437
$9,154,342
$0
$0
$5,820,416
$7,636,385
$0
$0
$0
Thabo Sefolosha
$3,600,000
$3,900,000
$0
$0
$0
$3,090,042
$0
$0
$0
$0
Nick Collison
$2,929,332
$2,585,668
$2,242,003
$0
$0
$2,445,480
$3,245,151
$4,442,612
$0
$0
Eric Maynor
$2,338,720
$3,351,386
$0
$0
$0
$2,253,061
$12,250,000
$12,250,000
$12,250,000
$12,250,000

That’s not even the entire roster, just the guys in the playing rotation who make the most money. But an obvious problem is on the horizon – how can you pay Durant, Westbrook and Ibaka, plus Perkins, and have room for Harden?

Ibaka only averaged 9.5 points, 7.5 rebounds and 3.6 blocks for the Western Conference champs, but he’s also only 22 years old (he turns 23 in September). Even though Tyson Chandler won defensive player of the year, many would argue Ibaka is the NBA’s best defensive player.

Harden, the NBA’s top 6th man, struggled in the NBA Finals, but it shouldn’t minimize a terrific season – 16.8 ppg, 49 percent from the field, 39 percent from deep. Harden, who turns 23 this week, is emerging as one of the best young shooting guards in the NBA. With so few big-time free agents hitting the market in 2013 – if Howard stays with the Lakers and Chris Paul remains with the Clippers, it’s a very bleak crop – OKC and Harden will probably be one of the top storylines next season.

Guess we’ll soon find out how much the Thunder value Harden. Other teams will offer Harden the max – Charlotte? Detroit? Would Cleveland be interested despite drafting Dion Waiters? – and OKC won’t be able to without majoring tinkering, like unloading Perkins and sacrificing valuable role players (think Collison and Sefolosha). If the Thunder believe shooting guards grow on trees, and they’ve got enough offense in Durant/Westbrook, then they’ll like move on. Is Harden already one of the league’s elite shooting guards? Or is he benefiting from playing with two of the NBA’s Top 10 players?

If OKC knows it can’t afford him, wouldn’t it just trade him so as not to lose him for nothing? Clearly, GM Sam Presti knows something nobody else does. Because if he’s able to lock up Durant, Westbrook, Ibaka and Harden for the next five years …