Adelaide United's Brazilian midfielder Cassio believes the quality of players coming to the A-League will improve it greatly.

The 29-year old, who has vowed to return to his best this season, is confident that the standard of the competition will be at its best in 2009/10.

"It is very good for the competition with quality players coming in. It makes everyone lift the standard," said Cassio.

"You have Perth Glory, with three Socceroos coming home, and Culina at the Gold Coast.

"There's Karol Kisel at Sydney FC and Robbie Fowler will be great with North Queensland. These big names come and generally want to prove they are great players."