ALAN Shearer admits that he is frustrated for Charlie Austin after he was ruled out for up to a month with injury and believes the only thing standing between the Saints striker and greatness is his fitness woes.

After his £4m January move from QPR, Austin had started to look more settled in Ronald Koeman’s side, winning his first start against Chelsea after a number of substitute appearances.

However, the 26-year-old hotshot was dealt a cruel injury blow in the 2-0 defeat at neighbours Bournemouth last week, cutting a frustrated figure as he hobbled down the tunnel on the hour mark.

Subsequently, Austin was ruled-out for up to a month with his third hamstring problem of this season.

Former Dell icon Shearer – being the Premier League’s 260-goal all-time top-scorer – knows what it takes to be prolific in the top-flight.

And he reckons that Austin has it in him to score season after season in the elite, but that he needs to shake-off the constant fitness problems.

“The only thing for Charlie is staying fit,” Shearer said. “He’s had that problem for a while, but for £4m it was a no brainer.”

“That is his problem – staying fit for long periods. Until you do that, it’s going to stop you getting to the top level.

“His finishing’s very good. He’s a goal scorer. He’s done well and knows where the goal is. He has to stay fit season after season.

“He has to prove his fitness for a long period of time before people can say he’s a top-class player.”

Shearer had his fair-share of injuries during his top-flight career, which started at Saints in 1988 and saw him go onto play for Blackburn and Newcastle.

He scored 43 goals in 158 appearances during his time at The Dell and went onto become the Premier League’s top marksman, scoring 260 times in 441 games.

“I’m sure Saints are doing everything to get Austin fit and keep him fit over a season, not just over six or seven weeks and pick up another silly injury,” Shearer explains.

“It is frustrating because I’ve been there myself. I’ve had serious injuries.

“I didn’t have really niggly injuries up until the end of my career, I just had serious ones.

“If they can get him fit, then they’ve got a really good player on their hands.

“He certainly knows where the net is.”