After a relative lull in product introductions, Cadillac has a pipeline of new vehicles ready to boost the brand's fortunes. Or so the General Motors division hopes.

In early 2016 Cadillac launched the XT5 crossover and CT6 sedan, following it up with a refreshed XTS in late 2017. Next year brings bigger news in the form of the XT4 compact crossover, with at least one other crossover waiting to plug another hole in the brand's utility lineup.

But what about Cadillac's older sedan lineup - the one that's not bringing in anywhere near the passenger car volume the brand once enjoyed? There's a long-range plan to deal with that, but first the company has some careful surgery planned.

Going by GM VIN code documents submitted to the National Highway Traffic Safety Administration for the 2019 model year, it appears changes are afoot for both the ATS and CT6. The smallest Cadillac offering, the ATS, is listed as a coupe-only proposition for 2019. Powertrains carry over from the previous year, but there's no sedan in sight.

The CT6 line drops its entry-level 2.0-liter turbocharged four-cylinder for 2019, with the 3.6-liter V6 serving as the powertrain floor. The 2.0-liter remains in the higher-end plug-in hybrid model. With the exception of that variant, all-wheel drive is standard across the range.

Both the CTS and XTS carry over from 2018 unchanged.

When asked to comment on the ATS sedan elimination (or potential omission), Cadillac wasn't in the mood to talk. The company wouldn't comment on future products, though Cadillac product communications representative Donny Nordlicht was happy to focus our attention on the XT4 bowing in 2018. (Interested in the XT4? Here's a peek at your XT4.)

2017 Cadillac CT6 - Image: Cadillac

The ATS coupe appeared for the 2015 model year, offering a buyers a handsome vehicle in a bodystyle whose popularity is shrinking faster than George at the pool. Actually, the same can be said for the ATS line overall. U.S. sales have fallen each year since 2013, the model's first full year on the market. Over the first 11 months of 2017, ATS sales are down 37.5 percent compared to last year. In November, just 831 ATS models moved off dealer lots - the lowest number since the model's first month on the market, September 2012.

Under NHTSA rules, an automaker can submit information on upcoming models until 60 days before the start of production, so it's possible Cadillac's 2019 lineup isn't yet set in stone.

Should the changes occur, it shouldn't come as a huge surprise. The ATS, CTS, and XTS are due to disappear after that model year. This past summer, Cadillac president Johan de Nysschen described the brand's plan to "rebalance its sedan portfolio," stating that a CT5 sedan will target buyers in the $35,000 to $45,000 range, with a smaller sedan arriving later to fill a lower price bracket. The remaining CT6, he implied, would go further upscale - and potentially further downscale.

After seeing the changes to the 2019 CT6, the latter possibility doesn't seem as likely anymore.