The 20-year old England-born Australian will return to his adopted country in time for the A-League finals and will be available to play for the Reds in the play-offs.
Initially the move is a four week stint with the possibility of a further two-year contract.
Adelaide coach Aurelio Vidmar said the club needed a replacement to cover the injured Jason Spagnuolo.
“We needed some strength in the midfield because we’ve been a little bit depleted with players in the midfield, so we’ve made some contact over the last couple of weeks and it’s a good opportunity for him to try and play some senior football,” Vidmar said.
“We’ll just have to see how he goes over the next couple of training sessions, and see where he’s going to fit in, but he’s certainly going to be an asset for us.
“He’s a big lad, he’s got very good technique, is someone who likes to get forward, a box to box type of player and that’s certainly what we’ve been missing over the last few weeks.”
Griffiths said he was looking forward to the challenge.
“The opportunity just presented itself at the right time for me and obviously I had a look at a few other options, and this one just appealed to me,” Griffiths said.
“Depending on what the gaffer wants to do with me, if given the opportunity then I think I can make an impact and that’s what I want to do as soon as possible.”