The 26-year old Canadian international is out of contract with the Dynamo and is exploring his options in Europe courtesy of a training stint with the Stags who currently sit second bottom on the Scottish Premier League table.
Along with out-of-contract forward Macoumba Kandji, Hainault is unlikely to return to Houston according to president Chirs Canetti.
"On both Andre and Mac, there have been no conversations whatsoever at this point that would indicate that their No. 1 priority is to return to the Dynamo," he told MLSsoccer.com.
"They're out there exploring other options and we're moving forward with the club and looking to build the team with our goals in mind.
"In the event that their process changes, we'll be happy to talk with them and welcome them back if in fact the opportunity still exists."