*Following Sentence is Grammatical

A puzzling construction in German struck me this afternoon. The following sentence in German is grammatical:

Dann sagte er folgenden Satz: …
Then said he following sentence: …
‘Then he said the following sentence: …’

That is, the object of “say” here is apparently a bare singular noun phrase, consisting of just an adjective and a noun. Now, German has bare plurals like English but like English it doesn’t have bare singular (count) NPs. So, how come that sentence is grammatical?

An obvious idea is that the adjective here has morphed into something like a demonstrative determiner (used only meta-linguistically to refer to the following material). A quick Google search shows that the construction is fairly common.

I am not much of an expert on German. Has this been looked at by anyone? Do other languages (Germanic or otherwise) have special meta-linguistic, demonstrative determiners?