Once the main piece acquired in the Oklahoma City Thunder's biggest trade in franchise history, Jeremy Lamb is now part of a footnote deal on draft day for a second-round pick and a player that will be waived.

According to league sources, the Thunder are trading Lamb to the Charlotte Hornets in exchange for a future second rounder and Luke Ridnour's non-guaranteed contract, a move that's primarily about clearing a roster spot and some money off the books.

Lamb, of course, was seen as the main return for the Thunder in their blockbuster -- and controversial -- 2012 deal that sent James Harden to the Rockets. The 12th overall pick that year out of Connecticut, Lamb spent most of his rookie season in the D-League but still figured to play a part in the Thunder's future at some point. Instead, he's been shipped off in a simple numbers move.

Before trading Lamb, the Thunder's roster had 13 guaranteed contracts, and with the team intent on retaining both Enes Kanter and Kyle Singler in restricted free agency, that would put them at the maximum 15. And that doesn't count the 14th pick in Thursday's draft, something the Thunder plan on using, presumably on a backcourt player now that part of that positional logjam has been somewhat cleared. The Thunder will also save some money by shaving off a bit of their luxury tax payment.

But how did Lamb, still just 22 years old and a player who was supposed to be the future replacement for Harden, end up being unceremoniously traded for a low-level pick?

The simple explanation is that Lamb just wasn't as good as the Thunder anticipated. It's important to note he wasn't exactly Sam Presti's first choice when he began shopping around for potential Harden suitors. Presti made calls to the Warriors for Klay Thompson, the Wizards for Bradley Beal and the Raptors for Jonas Valanciunas but was rebuffed everywhere. The Thunder tried to sell the deal they got as the one they wanted, but in reality, it was their third or fourth choice -- primarily because the organization was never entirely sold on Lamb.

What the Rockets had, though, in addition to Lamb was a stop-gap veteran guard in Kevin Martin who could help fill OKC's Harden void in the present, along with a future prospect in Lamb, plus future first-round draft assets. Assuming Lamb panned out as an adequate bench piece, the haul should've been acceptable. Because on paper, it looked decent: Lamb was billed as an offensive specialist, a player who could space the floor and attack the basket using floaters and runners. He's 6-foot-5 and exceptionally long with a near 7-foot wingspan, so eventually the defense would come.

But from the moment he arrived in Oklahoma City, Lamb never quite fit. He only appeared in 23 games as a rookie, all in mop-up duty. He appeared in 78 his second season in 2013-14 and appeared to have a foothold in the rotation with an impressive two-month stretch averaging 10.7 points on 45 percent shooting in 23 minutes per game. But after a February slump, Lamb's minutes dipped, with him eventually finding the bench again as the Thunder signed Caron Butler, who was waived midseason by the Milwaukee Bucks.

Lamb's third season was supposed to be the one for him to finally make some sort of leap. He pledged in the offseason before to remedy his biggest flaw -- defense -- and came into training camp committed to winning a spot in the rotation, possibly even the starting lineup. Instead, he started the season injured, missing the first five games, before returning and putting together an incredible five-game stretch in early December when he averaged 15.2 points on 77 percent shooting. Obviously not sustainable production, but Lamb was showing flashes of his potential. Three poor shooting performances followed, and in the fourth game, Lamb was handed a DNP-CD by Scott Brooks.

That's Lamb's tenure in Oklahoma City summarized perfectly. Flashes of promise, followed by flashes of disappointment, followed by a spot back on the end of the bench. Brooks clearly had a very short leash on Lamb, which surely didn't help with confidence, but that stemmed largely from his defensive inconsistency. Or at least that seemed to be the case.

“I mean, it probably has to do with defense,” Lamb said at the team's exit interviews in April. “Different things. But that’s a question for coach.”

Add that with his sleepy demeanor and perceived lack of intensity on the practice floor, and it's easy to see why a grinder like Brooks wouldn't favor Lamb. But with new coach Billy Donovan taking over, it seemed as if maybe Lamb would have new life in OKC. Especially considering the shooting guard position is anything but firmed up for the Thunder.

Instead, Lamb was shipped off to satisfy some mathematical rules.

“I just want an opportunity,” Lamb said in April. “I’m focused on getting better. If the opportunity is here or it’s somewhere else, I can’t really focus on that. I’m just going to try to get better, work on my game, focus on my game and whatever happens, happens.”

Well, that opportunity is indeed going to be somewhere else. And now that he's the guy traded for a non-guaranteed contract and a second-round pick, and not James Harden, maybe Lamb can make the most of it this time around.