The Germany international has been struggling to hit his usual best in the second half of the season and has become less decisive for die Konigsblauen since the turn of the year.
And Keller has urged the youngster to focus on the creative aspect of his game once more.
"I had a long talk with Julian this week. He has changed his game a bit. He does a lot of running and is always on the move. I told him that this shouldn't affect his creativity, though," Keller told Goal.
"He does a lot of running, but seems to be missing some courage at the decisive moments. This used to be one of his strengths.
"He lost his creativity a bit or has been hesitant in one-on-ones. I showed him this on video and he completely agrees with me.
"We need his creative spark. He definitely possesses that extra bit of creativity."
Draxler has made 24 Bundesliga appearances so far this season, scoring just once.
The 20-year-old was heavily linked with a move to Arsenal in the January transfer window, but the move eventually didn't materialise. His current contract with Schalke is due to expire in 2018.