Maryland Gov. Martin O'Malley. (AP Photo/Patrick Semansky)

O’Malley last appeared as a convention speaker in 2004, when the party gathered in Boston and he was still mayor of Baltimore. That address focused largely on homeland security in the wake of Sept. 11, 2001 and drew mixed reviews.

In the years since then, O’Malley’s stature in the party has grown significantly, accelerating with his election as chairman of the Democratic Governors Association in December 2010.

The two-term governor has now set up a national political action committee, is a surrogate this year for President Obama and is often mentioned as a potential 2016 presidential candidate.

O’Malley’s speaking time at this year’s convention in Charlotte is not expected to be announced Monday.