Dec 16, 2015; Oklahoma City, OK, USA; Oklahoma City Thunder center Steven Adams (12) handles the ball in the post while guarded by Portland Trail Blazers forward Noah Vonleh (21) and center Mason Plumlee (24) during the third quarter at Chesapeake Energy Arena. Mandatory Credit: Mark D. Smith-USA TODAY Sports

The Portland Trail Blazers defense has struggled this season, but will they ever be able to have a good defense with their current group of players?

The Portland Trail Blazers are not good at defense right now. They currently rank 24th in the NBA in defensive efficiency and don’t look very likely to improve.

True enough, teams are shooting below league average on both uncontested threes and uncontested midrange shots against the Blazers. But percentages on uncontested field goals are pretty random, so it is likely that the Blazers have been getting a bit lucky on some of their opponents’ misses this season.

The Blazers also have by far the lowest — or luckiest — opposing field goal percentage on uncontested layups and dunks at 71.2 percent, while the league average is 84.7 percent. This essentially means that opponents are shooting 13.5 percent worse than average on uncontested layups and dunks.

Opposing teams’ field goal percentage on these shots is very likely to improve, which is another reason to believe that the Blazers’ already bad defense will likely get worse rather than better. (All of these statistics can be found at Nylon Calculus’s team ratings and statistics page).

None of this is a major concern for Portland right now. The Blazers aren’t looking to contend this year; they would probably be happy with just looking competitive, seeing development in their key young guys (especially Noah Vonleh), and picking up another talented young player in the lottery.

Young players and therefore young teams aren’t typically good at defense — focus, communication, help rotations, ability to defend the pick and roll – these are all things that usually improve as guys get older. The larger issue isn’t that the defense is bad now, it’s that there doesn’t appear to be an avenue to a good defense with the current roster.

Defending the pick and roll is hard but good perimeter defenders get through screens in quicker and more direct ways so that they can stay closer to their man. Here’s Damian Lillard also struggling to guard the pick and roll.

Lillard has an opposite issue as C.J. McCollum trying to get through screeners in that he often gets stopped dead in his tracks by the screener, forcing the Blazers big who’s defending the pick and roll to switch on to the ball-handler.

It’s early in the season and adjusted plus/minus statistics are very noisy at this stage but, Lillard’s DRPM is absolutely horrific at -3.62, making his DRPM the second worst out of all qualified point guards. That number will likely improve but it is another indicator (to go along with the eye test) that Lillard has not been very good on defense this season.

None of this means that the Blazers need to get rid of either Lillard or McCollum; both guards have been clear net positives in both the eye test and in advanced statistics. What this does mean though is that the Trail Blazers would need to have high-level defenders at the other three spots in the lineup to eventually have a top-10 defense, which is typically what is needed to be a serious contender unless you have a historically great offense (a la the Steve Nash Phoenix Suns).

The most prominent teams that have done this are the Golden State Warriors and the Houston Rockets. Both teams have high-usage guards who can carry an offense but have had poor defensive reputations for most of their careers in Stephen Curry and James Harden. Both teams surrounded their superstars with athletic players who either were or had the potential to be good defensive players.

The Warriors drafted Draymond Green, Harrison Barnes, Klay Thompson and Festus Ezeli, traded a poor defender in Monta Ellis for a strong defender in Andrew Bogut, and signed Andre Iguodala and Shaun Livingston. There is a common theme of athleticism, long arms, and defensive ability amongst all of the guys that general manager Bob Meyers and the rest of the Warriors front office acquired to surround Curry with.

The Rockets haven’t had as much success as the Warriors but the philosophy has been eerily similar. After trading for James Harden the Rockets signed Patrick Beverley (an elite point guard defender who doesn’t need the ball in his hands, allowing James Harden to dominate the ball) and Dwight Howard, drafted Clint Capela, and traded for Trevor Ariza.

Teams like the Warriors come around once in a generation and it would be unreasonable to expect any team to reach the heights that they’ve reached, but the results that Houston has gotten (multiple playoff appearances and a conference finals appearance) are as much as most franchises can expect unless they land a generational superstar.

Not all of Daryl Morey’s moves have been successes (Ty Lawson) but he has done a very good job of surrounding Harden with players who allow him to maximize his strengths by dominating the ball while trying to hide his flaws on the defensive end.

What is unclear for the Blazers is whether or not they are following the same philosophy of surrounding their ball-dominant and defensively deficient backcourt. They acquired three players who fit perfectly into this philosophy.

The Blazers got two young wings on cheap contracts in Al-Farouq Aminu (as I recently wrote about) and Mo Harkless, who both have tremendous length and athleticism, can guard multiple positions effectively and can close off passing lanes with their length.

Neil Olshey traded for Noah Vonleh, picking up an extremely young (turned 20 a few months ago) and raw big man with tremendous physical tools (6’9″ with a 7’4″ wingspan) and good athleticism, giving him the potential to be a very good defender.

Outside of those three guys though, no other players in the supporting cast appear to fit the ideal model to support Lillard and McCollum. Allen Crabbe has solid size (6’6″ with a 6’11″ wingspan) but is clearly an offensively minded player.

Meyers Leonard is a below-average defender (as I discussed briefly here) and Ed Davis (26 years old, 6’10″ and 7’0″ wingspan) and Mason Plumlee (25 years old, 7’0″ and 6’11″ wingspan) are athletic but lack the length to be high-level rim protectors and aren’t young enough that one could expect dramatic improvement in their games.

Plumlee in particular has rated as a really poorly rim protector this season (opponents are shooting 58 percent against his contest at the rim this season, 56 percent last season), likely due to him being a basketball T-Rex (his wingspan is shorter than his height).

It will be interesting to see whether Neil Olshey decides to stick with his current group of young players or try to replace them with better defensive players to surround the talented backcourt in Portland. While it would be hard to part with such a talented young guard in McCollum I wouldn’t be surprised if Olshey moved McCollum if the Blazers were able to get an equally valuable but more defensively oriented player to slide alongside Lillard.

It’s still very early in Portland’s path towards contention after the mass exodus of their starting lineup, so there may be many moves left in store. For now it’s not a big deal if the Trail Blazers have one of the worst defenses in the league but if this same group of guys is on the team when the Blazers are really trying to make the playoffs, don’t be surprised if we’re still talking about their issues on defense.