Dobson spent last season with Walsall while on loan from West Ham, making 26 appearances in all competitions and scoring one goal.
Following his summer switch to Holland, the 20-year-old played only five times in the Eredivisie for Sparta.
Dobson told Walsall’s official website: “I’m delighted to be back.
“When Jon (Whitney, Walsall’s manager) got in contact and said he was interested in taking me back, I threw myself at the chance.
“I loved my time at the club last year. I really felt like I kicked on as a player, particularly in the second half of the season.”
Whitney said: “George is a player who is really highly thought of here, not just from myself but the players as well.
“I’ve kept in touch with George over the last four or five months and I’d like to thank the chairman and the board for providing additional funds to get George in.
“It’s a really good signing and it’s pleasing to get him in on a permanent basis.”
The transfer is subject to international clearance.
Burton midfielder Martin Samuelsen will use the international break to recover from illness after pulling out of Norway U21's games.
Jonas Lossl is staying 'optimistic' over Huddersfield's chances of survival this season and has urged his team-mates to 'go for it'.