Date of birth
O’Brien became Neal Ardley’s first permanent signing when he joined from Bradford City in January 2019.
The experienced midfielder came through the ranks at Celtic and had spells with Dunfermline Athletic, Dundee United and Motherwell before moving south of the border with Barnsley.
He spent four seasons at Oakwell ahead of a switch to Coventry, where he made 70 appearances.
O’Brien had spells with Shrewsbury Town and Ross County before joining Bradford for the first half of 2018-19.
And he committed himself to Notts for the rest of the campaign, citing Ardley's keenness to sign him as a big factor in his decision, going on to sign a new contract in the summer.
Home and away kit: NCFCOSA
Boots and socks: The Greenwoods