If the sources who spoke to Auto Express are correct the most obvious avenue would be via the World Rally Championship. Current regulations favour sub-Impreza-sized vehicles, so this would require Subaru reworking its WRX STI significantly.
Another option being considered is endurance racing, culminating in a factory team at the 24 hour race at Le Mans. This alternative's biggest stumbling block is the lack of a clear link between the cars used by Audi to dominate the category and its showroom range.
Regardless of how it re-enters the sporting fray, the company will be looking to do so with a hybrid drivetrain, as it is planning to launch of series of hybrid models from 2018 onwards. According to Auto Express Subaru's hybrid drivetrain will feature regenerative braking and a continuously variable transmission, but a plug-in system has been ruled out due to high development costs.
The same sources have said that a sub-XV SUV isn't on the agenda, even though sub-compact SUVs have proven popular in a number of markets. For example, the Nissan Juke sells well in Europe, while the Buick Encore (sold in reskinned form in Australia as the Holden Trax) has been a surprise hit in the States.
With the company's stated preference to have an all all-wheel drive range powered by boxer engines in export markets (BRZ excepted, of course), entering the small SUV segment would require a massive amount of investment on Subaru's behalf, as it currently lacks both suitably sized platform and an appropriate capacity boxer engine.
The company's smallest export model is the Impreza, while its boxer engine range kicks off at the two litre mark. To fill out its domestic range, Subaru relies on badge engineered models from both Toyota and Daihatsu. While all of these models are available in all-wheel drive, they are powered by in-line engines.