With Rajon Rondo heading elsewhere, Marcus Smart is waiting in the wings.  (USATSI)
With Rajon Rondo heading to Texas, Marcus Smart is waiting in the wings. (USATSI)

Rajon Rondo joined the Boston Celtics on June 28, 2006. They acquired him by trading for the Phoenix Suns' No. 21 pick. The bigger news, that night, was that the Celtics had traded their No. 7 pick (and Raef LaFrentz' hefty contract) to the Portland Trail Blazers in exchange for Sebastian Telfair. Rondo was expected to play behind Telfair. 

Rondo on the move
Mavericks get... 
PG Rajon Rondo 
PF Dwight Powell 
Celtics get... 
PF Brandan Wright 
PG Jameer Nelson 
SF Jae Crowder 
2015 first-round draft pick 
Future second-round draft pick  

Little did anyone know that the city of Boston would watch Rondo turn into a four-time All-Star and make All-NBA and All-Defensive teams. He was a huge part of the Celtics' championship run in his second season, and he's made many memories in the playoffs since. It's startling, now, to think of him in another uniform, but he's headed to the Dallas Mavericks along with Dwight Powell, in exchange for Brandan Wright, Jae Crowder, Jameer Nelson, a first-round pick -- likely in 2016, via Yahoo Sports' Adrian Wojnarowski -- and a 2016 second-round pick. What does this mean for Boston?

Marcus Smart, welcome to the show. The rookie point guard couldn't believe how good Rondo was when he first played against him in September. He's had a chance to learn from the veteran for a few months, but things will be totally different now. While head coach Brad Stevens could decide to have Smart back up Jameer Nelson at first, that would be a bit surprising. Long-term, Smart is the guy, and you might as well let him learn on the job. Along with that, though, will come many rookie mistakes. And that means ...

Expect the Celtics to regress. How far will they fall? It's hard to say, and that probably depends on what the trade market is for Jeff Green and Brandon Bass. Boston's offense will likely take a massive hit without Rondo -- on a team with a shortage of creators, he was the man responsible for getting everybody open looks. Beyond that, though, even if Smart exceeds every expectation, the Celtics likely want to regress. They're half a game out of the Eastern Conference playoffs now, which is a little crazy, and they're obviously looking toward the future. You're probably looking at a starting lineup of Smart, Avery Bradley, Jeff Green, Jared Sullinger and Wright, but that could change without much warning. 

We'll find out how well Wright's skills hold up. And Tyler Zeller, too. The two former North Carolina Tar Heels are shooting about a billion percent this year (OK, Wright is at 74.8 percent, Zeller 63.6 percent), but we don't know how these two will do in this new context. Wright has an uncanny ability to finish around the rim, but the Mavs also set him up for alley-oop after alley-oop. Zeller almost never takes bad shots, but he had the luxury of Rondo getting in the lane, attracting attention and gifting him good ones. Is either one of them a starting-caliber NBA big? Are both? We'll see.

It's the end of an era. I'm sure Wright, Nelson and Crowder will fit just fine in Stevens' system. I'm sure some Boston fans are thinking about how those draft picks can be used or packaged to help the team down the line. Really, though, this deal is about moving on. Jeff Green and Avery Bradley are the only Celtics left who played with Paul Pierce, Ray Allen and Kevin Garnett, but neither of them were there for that title-winning season. Boston has had Pierce or Rondo on the roster since 1998. Fans have already warmed up to Smart's dogged defense and competitiveness, but it'll still take a little while to get used to this new reality.