Olof Mellberg bade farewell to Aston Villa with a warning they must strengthen if they are to build on this season.
Villa failed to qualify for the UEFA Cup but could yet squeeze into Europe after claiming a spot in the Intertoto Cup with their 2-2 draw at West Ham United.
Manager Martin O'Neill ultimately hopes to challenge for a place in the Champions League.
But Mellberg, who on Sunday played his last match for Villa before joining Juventus, says that will only happen if they retain their best players and make new additions to the squad.
"It will be difficult to break into the top four. At the moment Villa are trying to establish themselves just behind that," he said.
"That is not easy because a lot of sides are in the chasing pack and are competing for those positions.
"If we can establish ourselves for a couple of seasons just outside those Champions League places then maybe we can push into the top four.
"I know the club wants to keep their best players and they will have to if they are to ever challenge the top teams.
"To achieve their ambition they have to keep the squad together and add a few more players."
outstanding gesture
Mellberg brought down the curtain on his seven years at Villa with an outstanding gesture to fans.
The big-hearted Sweden defender spent over £40,000 ensuring that every one of Villa's 3,200 travelling contingent at Upton Park received a club shirt bought and signed by himself.
"It was my own idea. It was an unusual situation for me because I knew so far in advance that I was leaving at the end of the season," he said.
"During the last few months so many fans have asked me for a signed shirt and so I thought it would be a good idea.
"I would have liked to have done it for my last home game last weekend but I thought 45,000 shirts might be a bit too costly!
"I also wanted to do something nice particularly for the away fans because they have supported us and me throughout the year and they have been fantastic this season.
"This game had been sold out for quite some time so the club knew how many shirts to make and so I hope everyone got a shirt.
"I wouldn't be here, making the money I have from football if it was not for those supporters so the cost was not an issue."