At least one of Alabama's longtime commits will be playing college football elsewhere.

Four-star Texas linebacker Vernon Jackson decommitted from the Crimson Tide Tuesday and won't sign with Alabama during National Signing Day on Wednesday, a source confirmed.

Jackson, who had been committed to the Tide since September, took an official visit to Alabama January 19. However, he visited Texas January 12, TCU January 26 and then Texas A&M this past weekend.

This means that the Tide has three players that remain committed heading into National Signing Day, though one -- four-star linebacker Quay Walker -- appears likely to sign elsewhere and another -- three-star tight end Michael Parker -- appears likely to be a blueshirt.

The news that Jackson won't sign with Alabama was first reported by SEC Country.

Matt Zenitz is an Alabama beat writer for the Alabama Media Group. Follow him on Twitter @mzenitz.