The 20-year-old made just 11 appearances last term and manager Neal Ardley admitted he could not guarantee him more game time over the next campaign.
"With the pressures of fighting relegation last season, I wasn't able to offer Huw many opportunities," Ardley told the Don's website.
"At Huw's age and at this stage of his career, he needs to be playing first-team football. We can't guarantee him that next season and we know that there are clubs interested in him.
"It therefore seemed best for all parties that he be free to decide where he wants to go to further his career.
"I'd like to thank Huw for his contribution to the club and wish him well in his future career."