The NBA's trade season enters its next phase on Thursday, when players who changed teams during free agency can be included in deals. The Portland Trail Blazers have been a part of the always-churning rumor mill for weeks, as a swath of Rip City has been pining for an upgrade as the team has underachieved over the first 27 games of the season.

But it would be unwise to expect a deal anytime soon.

The Blazers, according to rival front office executives, are right to be included in the rumors -- they are expected to be active in trade talks leading up to the Feb. 23 NBA trade deadline. But activity doesn't always translate to action and swinging a deal for a quality frontcourt player, arguably the Blazers' biggest need, is complicated.

Although the Blazers can include new players Evan Turner, Festus Ezeli and Tim Quarterman in trades starting Thursday, league rules stipulate that the Blazers can't trade re-signed players Allen Crabbe, Moe Harkless, Meyers Leonard until January 15.

CJ McCollum can't be traded until after January 27, six months after he signed his contract extension with the Blazers. Crabbe can also veto any in-season deal since he returned to Portland after the Blazers matched a free agent offer sheet from the Brooklyn Nets. Portland has future first-round picks to deal, but limited assets to get a something done immediately.

That won't stop speculation about potential moves, the biggest involving Kings center Demarcus Cousins. This rumor seems almost completely fan driven, but it's worth addressing since Cousins' name has been floated in trade rumors for much of the past three seasons.

Perhaps the biggest hindrance to any trade involving Cousins starts with the team he currently plays for. The Kings have repeatedly denied they want to deal their best player and don't seem to have much interest in trading Cousins. He's under contract through next season, so the "trade him before he walks" clock doesn't truly start ticking until next summer. Additionally, Cousins told ESPN's Marc Stein that he doesn't think he will be dealt.

Never mind the potential locker room concerns Cousins carries, at this point even the math doesn't add up on a Cousins trade. It's a segment of fans that want him in Portland, not necessarily Blazers executives, and the team he current plays for doesn't want to rush to move him.

There are other big men on the market that have been connected to the Blazers. The Mavericks are reportedly considering moving veteran center Andrew Bogut. But while his skillset seems to fit Portland's need for interior defense and rebounding, he's 32 years old with a long injury history and headed for free agency this summer.

Neil Olshey, the Blazers' President of Basketball Operations, has built the Blazers' roster with a core group of players who are similar in age and career arc and the goal is to let them grow and develop together. The Blazers aren't looking for a three-month gamble, they're looking for a long-term solution that can grow alongside their core.

Magic center Nikola Vucevic could also potentially be available in a trade. He's lost his starting spot and is playing less than 30 minutes a night for an Orlando team with plenty of options in the frontcourt. Vucevic would bring interior scoring and rebounding to the roster, but his limited defensive skills make him only a lateral upgrade that could cost Portland useful assets without addressing their biggest needs.

Milwaukee's Greg Monroe, a one-time Olshey free agent target, could also potentially be had in a trade. But his production has dwindled in a reserve role this season and he can opt to hit free agency in July. And, like Vucevic, Monroe's blend of low post offense and poor defense are answers to questions that the Blazers aren't asking.

That leaves Philadelphia's Nerlens Noel as the most reasonable big man target potentially on the trade block. Noel has been publicly angling for a way out of Philadelphia for three months, saying that the 76ers' logjam at center "doesn't make any sense."

In theory, he's exactly what the Blazers are looking for: an athletic 22-year-old with the defensive skills to defend the rim and contain ball-handlers in pick-and-rolls. But Noel also comes with clear concerns. He tore the anterior cruciate ligament in his right knee prior to his rookie season, missing all of 2013-14. He also sat out the first 23 games of this season after undergoing "preventative surgery" on his inflamed left knee. What's more, he will be a restricted free agent this summer.

While Noel makes the most sense in age and skills, there is no immediate deal the Blazers could likely make to acquire him before Christmas. The mechanics of the NBA's collective bargaining agreement demand that Portland wait at least a month before moving its most tradeable assets.

Perhaps the Blazers wait until January or even the trade deadline to make a move for Noel -- or someone else --but while trade speculation excites fan bases across the league, the reality is that there might not be a quick fix or home run move for the Blazers.

--Mike Richman

mrichman@oregonian.com

@mikegrich