Eckersley came through the youth ranks at Manchester United and made four senior appearances before joining Burnley in 2009.
The 26-year-old had loan spells at Plymouth, Bradford and Bury before joining MLS side Toronto FC in 2011.
Eckersley played over 50 times for Toronto before joining New York Red Bulls last season, where he made nine appearances.
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Oldham have confirmed Eckersley will wear the number 24 shirt during his time with the club.
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