Hoillet has long been linked with a move back to Germany, where he spent time on loan earlier in his career.
The 22-year-old Canadian-born striker also speaks fluent German and his brother plays there.
But he is still considering his options in England and a host of clubs have stepped up their interest in recent weeks.
Reports suggest that Tottenham, QPR, Liverpool, Newcastle and Everton have all had contact with the player's representatives in recent weeks.
Hoilett is currently believed to be in England with his family, continuing talks.
Borussia, though, hope that the lure of Champions League football will win the day for them.
Support the USA national team with an official 2013 Centennial soccer jersey from Nike. Its Official.
Neymar's move from Santos to Barcelona is no doubt the biggest summer transfer.
Germany is one of the top teams ever and they will play the US on Sunday.
The adidas Nitrocharge is the most talked about new cleat in years. It was released on May 15 and will take your pitch by storm.
The hoop soccer jersey is classic and cool. The USA hooped jersey is perfect for every fan. Get in the Gear.
Barcelona will wear this new home soccer jersey next season. They also have a new away jersey. Get them both.
The Nike Hypervenom is the latest cleat silo from Nike. It will change your game and is worn by the game's top players.
England will debut their new away jersey against Brazil at the Maracana Stadium on Sunday. Get in the Gear
The USA will wear their blue away jersey against Jamaica in their World Cup qualifier on Friday night.
Jamaica is in need of a win against the U.S. Get the jersey of the Reggae Boyz.