The former Wimbledon champion is expected to play in his first tournament in three months at the ATP event in Germany following his late withdrawal from the French Open last month.
Hewitt has in the past tended to play only one tournament on grass in the lead-up to the third grand slam of year.
However he is desperately trying to gain as much match fitness as possible before a 13th straight trip to the famed south-west London venue.
There have been concerns over the former world No.1's fragile body following foot surgery in March.
The official reason given for him pulling out just hours before being due to walk onto court at Roland Garros was a left ankle complaint.
But it is understood he has suffered a flare up of a toe injury.
"He will definitely be heading to Halle next week (to defend his title)," said his manager David Drysdale.
"Everything seems to be going OK.
"Lleyton has been getting out on the court and had some treatment."
Grass has been the former world No.1's most successful surface, having won 101 of 125 matches on it during his career.
Only once in his last seven visits to Wimbledon has he been defeated by a player outside the top six.
Hewitt upset Roger Federer in the final in Halle last year before the Australian had his progress at Wimbledon stopped in the fourth round by Novak Djokovic in four sets.
"He has always enjoyed playing on the surface and it is a surface that he has done well on," said Drysdale.
"He wants to play as many matches as he can before Wimbledon."
The South Australian has not played since an opening round loss at Indian Wells in early March.
-AAPTags: sport, tennis, australia