Which Imam said that? Whats the context?
This is interesting.
The Imams (a) said all hadiths have to be referred to Quran and if contradicts to leave it, and if Quran affirms to follow, and if you don't know which of the two, to leave, till you find out.
However, this doesn't allow the stance to say Quran doesn't confirm. You have to show either it contradicts Quran or Quran affirms, while, they are arguing everything in terms of guidance can be found in both Quran and Sunnah, and they compliment one another.
So if you can't show Quran refutes a concept, can't say "Quran does not say". This is not allowed per hadiths.
And whoever denies a hadith without knowing is wrong, get's out of the realm of belief in Quran and Ahlulbayt (a) guiding nature per hadiths.
In reality, every component of Salah is in Quran, but not explicitly but with the Sunnah, we can see inward wisdom of the outward shariah, and confirm it in Quran.
While people write books in limited ways, the comprehensive nature of Quran in terms of guidance that it leaves no matter out, is part of the proof it's from God. But it's not easy to learn to use it and see everything in terms of guidance in there, and so Sunnah and hadiths are to be approached as well.