Ambulance Victoria spokesman Paul Bentley said the 19-year-old collapsed soon after 7pm at the Salesian College football oval in Macedon Street.

He was treated at the scene by a doctor and off-duty intensive care paramedic before ambulance crews arrived.

"He collapsed and went into cardiac arrest so his heart wasn't beating effectively," Mr Bentley said.

Paramedics treated him for more than an hour before he was transported to the Royal Melbourne Hospital. He arrived at 8.48pm in a critical condition.

Club president Rob Morrice said Buckman died about 20 minutes after arriving at the hospital.

"My understanding is that there was no history of heart problems with Stephen," Morrice said.

"Stephen has been playing for Rupertswood since the under-9s. He's been with us for 10 years.

"He loved the club environment. He was known as our gentle giant and always had a smile on his face. He was very popular with teammates.

"The Buckmans are a very loving family and terrific supporters of the footy club. Our hearts go out to them.

"As a club we're devastated by it."

The Rupertswood team dedicated its game last Saturday to Buckman, who also played cricket for the town until last year.

In a Facebook group created just hours after his death, friends remembered the much-loved 'Bucky', who graduated from Sunbury Downs College last year.

Matt McKay wrote: "To all Bucky's family and friends - he won't ever be forgotten. I don't think words can describe the character that Stephen was. Stephen Buckman, class of 2009 won't be the same without you!"

Natham McCall wrote: "My thoughts are with Stephen's family during this dark hour. Though I hardly knew him, he made an impression on the whole year level and the world is worse off without him. His death is truly a tragedy."

A vale on the club's website reads: "Our gentle, smiling giant. His personality and character will be missed but never forgotten. Bucky, you were a true clubman, and we will miss those great 'dukes'! We wish to express our sincere condolences to Sue, Gary, Michael and Ashleigh [Stephen's family]."

Stephen will be farewelled by family and friends during a service at 10am on Friday at St Andrew's Uniting Church in Sunbury.

*North Sunshine Football Club's Sean Wolfe died after an asthma attack on the field in the reserves clash with Yarraville-Seddon Eagles on May 15.