The defensively challenged Los Angeles Lakers are underwhelming, posting a 10-15 record since winning the inaugural in-season tournament. Now in ninth in the Western Conference, the Lakers struggle to get momentum to springboard into playoff positioning.

Could the team’s struggles stem from their 39-year-old superstar, LeBron James?

“We didn’t get back in transition and they ran out on us,” James told reporters following the 135-119 loss to the Houston Rockets (22-24) Monday night. “We didn’t get back, didn’t have a sense of care factor.”

James averages 25 points, 7.4 rebounds and 7.7 assists, and his efficiency is off the charts (52.3 percent from the field and 39.9 percent from three, the second-best percentage of his career).

However, James — the oldest player in the NBA — holds a defensive rating of 114, the lowest mark of his career. (Defensive rating is an estimate of points allowed per 100 possessions.)

James’ lateral quickness has diminished and he’s unable to consistently stay in front of his matchup. At this juncture in his career, the challenge of exerting maximum effort on both ends has become more pronounced, often necessitating a compromise in one area to sustain performance in another. James has chosen to sustain his offensive production.

“LeBron James’ offensive numbers look great,” Fox Sports’ Ric Bucher said on Jan. 17 on Sportsnaut. “That’s not making anybody else better… And defensively, he’s a nightmare.”

While James remains an exceptional talent, arguably capable of spearheading the Lakers (24-24) toward their 18th championship, there’s a noticeable change in his performance, particularly on the defense. He clearly can’t dominate on both ends as he did in his prime.

The Lakers — and especially James — are at a critical juncture as they continue their challenging six-game road trip, which includes games against the Boston Celtics (36-11) and New York Knicks (30-17).

Without marked improvement on defense, Los Angeles risks falling further behind in the uber-competitive Western Conference. Heading into Tuesday’s game at Atlanta, the Lakers are tied in the loss column with the 12th-place Golden State Warriors (19-24).

James has battled “Father Time” for the past several seasons. This season, though, “Father Time” clearly has the upper hand against “King James.”