The official Agents of Shield Twitter has confirmed that Lucy's role for Season 2 of AOS is Elizabeth Hartley (or Isabel Hartley by some tweets but I'll go with Elizabeth since that's the name they used on the AOS Twitter)
The Hollywood Reporter says:
Among the revelations to the Comic-Con crowd: confirmation that Lucy Lawless will be coming on board the ABC series as a longtime SHIELD veteran.
"She's tough. She may have a knife that's always by her side," said executive producer Maurissa Tancharoen.
What is Agents of S.H.I.E.L.D About?
Marvel's Agents of S.H.I.E.L.D., or simply Agents of S.H.I.E.L.D., is an American television series created for ABC by Joss Whedon, Jed Whedon, and Maurissa Tancharoen, based on the Marvel Comics organization S.H.I.E.L.D. (Strategic Homeland Intervention, Enforcement and Logistics Division), a fictional peacekeeping and spy agency in a world populated with superheroes and numerous supernatural phenomena. The series is produced by ABC Studios, Marvel Television, and Mutant Enemy and is set in the Marvel Cinematic Universe, sharing continuity with the films in that franchise. It revolves around the character of Phil Coulson, with Clark Gregg reprising his role from the film series.
Agents of S.H.I.E.L.D. was renewed for a second season on May 8, 2014, which is scheduled to premiere on September 23, 2014.
For more information about Lucy's role on Agents of S.H.I.E.L.D go to the AUSXIP Lucy Lawless Agents of S.H.I.E.L.D subsite