tenses - "I didn't know you golf" vs "I didn't know you golfed"

While reading a popular author I came across:

"I left my clubs at home, so I can't play."

"Oh? I didn't know (that) you golf."

This sounds wrong, but presumably it was passed by at least one editor. To me, the past tense "golfed" would be more appropriate. But if this way works too, what sort of construct is it?