Caution: This question concerns the verb 'direct' followed immediately afterwards by an object.
To ameliorate readability, I eschew the use of blockquotes below, where I quoted the OED.
[Source:] [...] [In] a sentence with a single object (instead of a phrase that begins with a determiner such as "what to put on sale" or "which question to answer"), the preposition is needed.
Is above quote correct? It answers the entitled question in the negative.
Below, OED matches each definition of transitive-direct decide with a definition of transitive-INdirect decide.
Because 1a means the same as 1b, and 1d as 1e, prepositions like 'on, upon, about' appear extraneous. If I erred, then what are the functions and meanings of the postverbal preposition?
However, I recognise the necessity of some postverbal prepositions like 'between', because
'an arbiter decided X and Y' differs from 'an arbiter decided BETWEEN X and Y'.
decide, v.1 [=] I. To come or bring to a resolution or conclusion.
1. a. trans. To arrive at an opinion or conclusion about [...]
b. intr. To come to a decision or conclusion. Chiefly with on, upon, about, etc.
d. trans. With infinitive, clause, or direct speech as object. To determine upon as a course of action; to resolve to do (something) or bring (something) about. Also in passive with anticipatory it.
e. intr. Chiefly with on, upon, etc. To come to a firm decision with regard to future action or intention; to determine on or opt for something; to select something from several alternatives.