The Kangaroos co-captain has reaffirmed the club's ongoing support for Thomas after his sacking last week, saying the forward will not be thrown to the wolves.
Thomas was let go by the club after an AFL investigation, for threatening a woman and other misconduct.
Simpkin spoke on Monday, just hours before police confirmed they were investigating Thomas.
"Police spoke with a 23-year-old Ormond man in relation to an ongoing matter," Victoria Police told AAP.
"It would be inappropriate to comment further at this time."
It was the latest in a series of off-field controversies involving Thomas.
"It's obviously a really sad situation for everyone involved - the football club, the community and Tarryn himself," Simpkin said.
"We're definitely not throwing him to the wolves. We want to support him as much as we can.
"I've had a good relationship with Tarryn over the last five-six years he's been at the club.
"I hope to see him playing AFL football again, as long as he gets all his stuff off-field sorted.
"He's obviously a great talent. He could be a very special player - unfortunately it won't be for our football club."
Former Kangaroo Tarryn Thomas gathers a possession against Essendon. (Morgan Hancock/AAP PHOTOS)
Simpkin agreed with Kangaroos football manager Todd Viney, who said last week there are two sides to Thomas.
"You see Tarryn at the club and he's such a great kid," he said.
"Then obviously he has a few issues that go on outside ... the footy club.
"We wish him all the best, the club supported him as well as they could and now it's up to him to make change."
Asked if teammates could have done anything differently in regards to helping Thomas, Simpkin replied "I don't think so".
Thomas has been a major issue over the summer for North as they prepare for their second season under coach Alastair Clarkson.
The Kangaroos only managed two wins last year as Clarkson had extended time away from the club because of the Hawthorn racism controversy.
"I have no doubt we'll win a lot more games than we did last year," Simpkin said.
"We'll win more than two games.
"To have him (Clarkson) for the back half of last year and have a clear understanding of what we wanted to work on ... it's been a very good pre-season."
AFL
11°C