From the outside, it appears Dirk Nowitzki is doing normal Dirk things. His scoring is down, sure, but he's still at a little over 18 points per game in fewer minutes and putting up a PER over 20.

He started the season looking like his normal efficient self. Dirk was coming off a season in which he almost hit on another 50-40-90 season and hit 60 percent or better of his shots in six of the Mavs first 10 games. He looked so good, I remarked earlier in the season that Dirk is timeless and isn't showing any signs of slowing down.

About that. Dirk might be slowing down.

I've been watching Dirk closely over the last month and a half and have held my tongue for most of that time. I didn't want to rush to conclusions, that Dirk would come out of a little shooting slump and regain form as the terrorizing offensive player he's been throughout his entire career. Except it's not happening.

Despite his ridiculously hot start, Dirk is shooting a mere 46.4 percent from the floor and 34.1 percent from three. Those numbers don't look awful but they certainly aren't up to Dirk's standards -- that field goal percentage would be the sixth worst mark of his career and the 3-point shooting would be tied for his second-worst mark ever.

It seems crazy to think, but Dirk's hot start is actually hiding just how horrible his shooting has been since December. He shot 43.5 percent overall and 27.8 percent from three. Read that again. DIRK FREAKING NOWITZKI SHOT LESS THAN 30 PERCENT FROM THREE. FOR AN ENTIRE MONTH.

Just wait, it gets even worse. A lot of us on the Mavs Moneyball staff have tweeted and discussed in our email chains about how Dirk appears to be missing more open shots then we can ever remember. Game after game in the last month or so, it just seems like Dirk is missing an unfathomable amount of open midrange jumpers -- his bread and butter.

Unfortunately, the eye test plays out. According to NBA.com, Dirk is hitting 47.7 percent of his "open" two point shots that are greater than 10 feet from the basket -- midrange jumpers, essentially. NBA.com defines open as the closest defender 4-6 feet away. For comparison, Dirk shot 51.8 percent on those shots last season.

Those patented Dirk face-up iso jumpers? Dirk's missing a ton of those too. On two point shots 10 feet from the rim with the closest defender 2-4 feet away, Dirk is hitting just 43.8 percent. Last year? He hit 51.1 percent of those shots.

What about open three-pointers? Dirk is missing those too. On what NBA.com calls "wide open" three pointers (closest defender six feet away or farther) Dirk is shooting 35.2 percent. Let that sink in -- Dirk is currently an AVERAGE NBA three point shooter on what are essentially warm up three pointers without a defender in sight. Last year, Dirk hit 45.1 percent of those three pointers.

Like I mentioned earlier, Dirk is missing more open two-point jumpers than normal. In fact, overall, he's hitting just 43.5 percent of shots from 8-16 feet. Again, last year Dirk was hitting 49.8 percent on those shots. It gets even worse -- in the last 15 games, Dirk is hitting just 40.8 of those shots.

That 8-16 range is Dirk's sweet spot -- it's usually the area of the floor where he takes either the most or second-most shots over a season.

Now this is where I would love to say what the problem is. Is it Dirk's new shot that he was tinkering with? It can't be lack of rest as Dirk is playing the fewest minutes per game since his rookie year and he's already had a handful of games off. Is he hurt? Maybe. Our own Kirk Henderson thinks so and I do remember Dirk saying his back was hurting him during the double-overtime win in Chicago. He also mentioned being sick a while back. But the Mavs aren't saying anything really, and Dirk hasn't given much to the media other than generic stuff like "I've got to be more efficient."

My biggest fear, of course, is that it's none of those things. Dirk is 36-years-old and has a tremendous amount of minutes and games on his body. Perhaps that's finally catching up to him. Perhaps Dirk is indeed mortal. I hope not. It pains me to watch Dirk continue to clang three pointers and open jumpers. It's insane to think he's been one of the Mavs worst three point shooters this year. That's especially alarming when you consider the Mavs have very, very few consistent three-point threats on the roster beside Dirk.

For as much as the Mavs have tried to ease the pressure off Dirk -- picking up Monta Ellis and Chandler Parsons to ease the scoring, Tyson Chandler to shore up the boards and let Dirk spot up more, Rondo to be a true facilitator -- he's still the Mavs engine. They will only go as far as he will take them.