The 33-year-old missed the autumn internationals but will now hope to be back in contention when his country begin their Six Nations campaign against Wales on February 2.
Leinster coach Joe Schmidt also offered encouraging news over two more Ireland internationals, Rob Kearney (back) and Luke Fitzgerald (neck).
"Brian is out there for his first on-field session and Rob Kearney is due out on the pitch next week," Schmidt told the Irish Independent.
"Luke is back on the pitch a while and we're looking at either the home game against Connacht at the RDS on December 29 or for the Edinburgh match away at Murrayfield the following week."
The trio's availability for the Six Nations would be a huge boost to national team coach Declan Kidney, particularly with wing Tommy Bowe ruled out.
Ireland were also without forwards Paul O'Connell, Rory Best, Stephen Ferris and Sean O'Brien for the November series.