Former Hull FC and Hull KR fullback has re-joined Super League side St Helens after a short stint with the Wests Tigers in the NRL until the end of the 2016 season.
The 27-year-old fullback left St Helens at the end of the 2014 season to join the Wests Tigers in Australia, where he appeared for the NSW side, failing to make a first-team appearance.
McDonnell appeared three times for St Helens in 2014 after joining them on loan from Hull FC, but broke his jaw which ended his season in September.
The announcement comes just under 24-hours after the announcement of utility player Lance Hohaia retiring from the sport due to an on-going concussion-like symptom after matches.
On the announcement, Saints Chief Executive Mike Rush told the official website: "It's clear with Jonny Lomax out for the season and Paul Wellens currently sidelined that we need cover at full back as well as in the backs.
"Shannon can cover a number of positions and we'd like to thank Phil Moss at Wests Tigers and his agent Steve Gillis for making it happen.
"He did a great job last season and we look forward to welcoming him to St Helens once again."
Shannon McDonnell will wear the number 34 jersey for the remainder of the season.
The 27-year-old fullback left St Helens at the end of the 2014 season to join the Wests Tigers in Australia, where he appeared for the NSW side, failing to make a first-team appearance.
McDonnell appeared three times for St Helens in 2014 after joining them on loan from Hull FC, but broke his jaw which ended his season in September.
The announcement comes just under 24-hours after the announcement of utility player Lance Hohaia retiring from the sport due to an on-going concussion-like symptom after matches.
On the announcement, Saints Chief Executive Mike Rush told the official website: "It's clear with Jonny Lomax out for the season and Paul Wellens currently sidelined that we need cover at full back as well as in the backs.
"Shannon can cover a number of positions and we'd like to thank Phil Moss at Wests Tigers and his agent Steve Gillis for making it happen.
"He did a great job last season and we look forward to welcoming him to St Helens once again."
Shannon McDonnell will wear the number 34 jersey for the remainder of the season.