The 22 year-old has built a reputation for himself in the Bundesliga and in the Champions League with Schalke, leading to interest from a number of clubs.
The German international's contract runs out at the end of the current season and he may be set for a move to the Premier League, with Arsenal and Liverpool heading the queue.
One factor that could scupper a deal to Liverpool is the fact that his father was born in Merseyside and is a die-hard Everton fan.
Holtby has indicated that a move to the Gunners would be the preferred option as he talked up their style of play under French manager Arsene Wenger.
"Everton is always close to my heart and I've always loved Arsenal for their style," he told the British media before Schalke's recent Champions League match against Arsenal. said Holtby.
"It will be a decision of the heart, I won't play around with the club,"
"The opportunities are there.
"My agent has received offers. I'm waiting to make a decision."