1. Is he healthy?

The drop in his scoring efficiency can be explained by the fact that he is simply not getting shot attempts near the rim at a healthy enough frequency like he used to. Check out his shot table below, courtesy of Basketball-Reference.com:

Notice the column for "Distance"; this is the average distance away from the rim for his field goal attempts. Note how its increased pretty much every year. During his most efficient years, Rondo took around half of his field goals around the rim; that has slowly declined to only 30.9% last year. As a result, his field goal percentage has declined right along with it, and thus his offensive efficiency is now in the cellar.

Onlookers have theorized that Rondo has lost a step athletically and he is simple unable to get to the rim. But watching footage of Rondo doesn't make it seem like he's lost much explosiveness. You be the judge:

Here is what Rondo looked like in transition in 2012:

Slashing in a pick-and-roll in 2012:

Slashing off of a pick-and-roll in 2015:

Its tough to actually say definitively whether Rondo is slower or not based on stats or short clips. Its entirely possible that other factors could be affecting him athletically, such as a lack of stamina to keep exploding to the rim repeatedly. But just from the eye test, it seems like he can still get to where he wants to the same way he used to. This is a dark cloud hanging over Rondo's head as he nears that magic thirty mark in age.

2. Does he have a place in the modern NBA?

There are other possible explanations for Rondo's decline besides diminished explosiveness. Another is that Rondo has been left behind by the modern NBA; that because of a heavy emphasis on three point shooting, motion offenses, and space, that Rondo's skillset (a ball-dominant playmaker with a shaky jumper) has become obsolete.

But that still leaves the question of why Rondo's scoring efficiency was a dumpster fire ever since he returned. Both last year and this year, Rondo's teams have been better offensively when he's been off the court than when he's directing the show. Could it be that NBA defenses have figured out how to eliminate Rondo's scoring efficiency and nullified as a positive force on a team's offense?

Maybe. We won't really know the answer until the season kicks off in October, but here's the argument for why the answer is no.

In reality, Rondo's effect on a team's offensive rating has been negative since the 2012/2013 season, the year before his injury. The Celtics finished 42-40 and squeaked into the Playoffs as the seventh seed. But, more critically, it was the year Ray Allen had departed for Miami, and where both Paul Pierce and Kevin Garnett showed serious signs of decline. Both Pierce and Garnett posted their worst TS% marks in nearly a decade; it was clear that a team built around Pierce and Garnett as core pieces were finished as a contender.

If you look at Rondo's play in the last year, the only way he got quality looks in the halfcourt was if the defense made a mistake. Lets look at the following play as an example:

In this play, note how much attention the defender is paying to Olynyk and Green. Rondo takes that tiny daylight of space and makes an impressive floater off the glass. Imagine if this play is run with Cousins and Gay? That daylight probably gets bigger.

3. Will he buy in?

Its safe to say that Rajon Rondo is not the easiest personality to get along with. If you haven't already, I highly recommend reading Baxtor Holmes' phenomenal piece on Rondo's personality. Its deep with incredible stories of broken flatscreen T.V.s, the cussing out of assistant coaches, and the merciless destruction of hospitalized children at Connect Four.

Its that same fire that makes him such an unwieldy personality to get a grasp on for a coach. Tubby Smith, Rondo's coach in college, benched him for six games because the two clashed. Doc Rivers reportedly nearly came to blows with him in 2013; Rondo was rumored to be a big reason for Doc's departure to the Clippers the following offseason. After being traded to Dallas, Rondo and Rick Carlisle publically engaged in a shouting match in February that resulted in a one game suspension, and his exit from the first round Dallas/Houston series needs no further comment. By Rondo's own admission, he hadn't played defense in two years because of Avery Bradley's presence allowing him to coast on one end.

How does this project to the Kings under George Karl? Not all is doom in gloom. One way that Karl would be different from Rondo's previous coaches is the freedom he like to grant the players on offense. In other words, to borrow from the mantra of Russell Westbrook's fans, to let Rondo be Rondo. Karl won't call a play every time down the court. Karl, ever since his bout with cancer, has considerably mellowed in his verbal altercations with players.

Ultimately, regardless of how many reasons we can conjure for why Rondo has been bad the last few years, if it doesn't work here in Sacramento, it's probably the end of Rondo as an elite player in this league. He's got a laissez-faire coach, he's surrounded by offensive talent and depth, and he has all of the motivation in the world to prove that he's not finished. It'll be one interesting ride, but until takeoff, the questions loom large.