The club confirmed on Monday that Hornsby, who had been at the Saints for six seasons after more than a decade with Richmond, will leave as part of St Kilda’s off-field changes following a year in which Brett Ratten’s side failed to make the finals.
Former captain Hamill had been on the club’s coaching staff for a decade, while Skrobalak had also been at the Saints since the early days of Alan Richardson’s tenure.
Earlier this year, The Age revealed that Hamill had met with Carlton about a potential return to the Blues where he played in the club’s 1999 grand final side before heading to Moorabbin at the end of 2000.
“Aaron and Adam have both had impact on countless players during their time on our coaching panel, with Aaron also serving as an important link to our club history, a role I’m sure he will continue for a long time,” Saints chief operating officer Simon Lethlean said.
“Matt’s hard work and dedication has been key in our high-performance program for many years, and we know his professionalism will no doubt result in many exciting future opportunities.
“Andrew is one of the best physios in the business and has laid a strong foundation for our team to continue delivering an extremely high level of support to our players moving forward.
“We thank all four for their contributions to the club and look forward to celebrating their achievements with the broader club once restrictions allow.”
The Saints struggled with a long and crippling injury list for much of the season, with key players such as Zak Jones, Rowan Marshall and Paddy Ryder all missing sizeable chunks of football.