Promising defender Mawson has been the subject of speculation surrounding a move away from the club over the summer.
Bristol City – managed by former Reds’ boss Lee Johnson – have reportedly seen a bid of £1million rejected while Wolverhampton Wanderers, Leeds United, Newcastle United and Queens Park Rangers have also been linked with the former Brentford player.
But wing wizard Hammill believes the best place for the 22-year-old to hone his talent is at Barnsley.
“There’s no better place to learn his trade as a defender than under Hecky,” said Hammill.
“He’s relatively young and he still has a lot to learn. Eventually it’s going to be his choice but obviously we want him to stick around as he’ll be a massive influence on how we’ll do this season.
“Him and Robbo are building a partnership that will be outstanding for years to come.
“It can be difficult, people’s heads do get turned, it’s only natural.
“I know Alfie well enough, he’s focused and he’s an outstanding player.
“The only advice I’d give him is in the past I may have rushed into a move and his ability will get him there. I think he’ll go all the way, I can see it.”
Barnsley host Derby County tomorrow afternoon in their first Championship game back at Oakwell.
The Reds are looking for their first points of the season after their opening day defeat to Ipswich Town.
Derby reached the play-offs last term and Hammill knows the Rams will be a formidable test for a relatively inexperienced Barnsley outfit.
The East Midlands side has done very little business compared to the Reds, who have added nine summer signings.
“Derby have always had a strong squad. I don’t think they needed to do much business – they’ve got a new manager in,” Hammill said.
“Their style of play will be attacking. They like getting the ball on the floor and pass it and that’s the right way to play and how we want to play, too.
“I think it’s vital that each and every game we go into it knowing we’re going to outwork them and outrun them.
“We need to win the key battles in each game, not just Derby.
“We want every Championship team playing Barnsley to go away thinking ‘that was a tough game’.”