Q: I recently read this in an online sports column: “The biggest question is just how valuable can he be.” I’m guessing that the author ended it with a period because the sentence as a whole is a statement, even though it contains a question. However, it seems awkward to me.
A: The writer probably intends the sentence to be an indirect question, not a direct one, and an indirect question doesn’t need a question mark.
But in that case we would have expected him to write “he can be” instead of “can he be.” The usual syntax for this kind of construction is “The biggest question is just how valuable he can be.”
The Chicago Manual of Style (15th ed.) says an indirect question “never takes a question mark” and “takes no comma” (pages 259 and 255).
The Chicago Manual gives some examples of indirect questions, including these: “How the two could be reconciled was the question on everyone’s mind.” And, “What to do next is the question.”
As for the sentence you’ve asked about, it can be written (as we noted above) in a way that would require a question mark: “The biggest question is, just how valuable can he be?”
Note the use of the comma. The Chicago Manual explains that “a direct question included within another sentence is usually preceded by a comma; it need not begin with a capital letter.”
The style manual gives this example: “Suddenly he asked himself, where am I headed?”
If you’d like to read more, we’ve written before on the blog about punctuating questions within questions.
Check out our books about the English language