The Sopranos actress will play new socially awkward agent Bishop, TVLine reports.
Though Wickersham is currently only signed for three NCIS episodes, her contract also contains a series regular option.
Currently recurring on FX series The Bridge, her past credits include an appearance on Gossip Girl and the 2011 film I Am Number Four.
NCIS will bid farewell to the character Ziva David in season 11's opening two-part story after actress Cote de Pablo opted to quit the long-running procedural.
De Pablo recently admitted that leaving NCIS was "not an easy decision".
NCIS season 11 premieres on September 24 on CBS.
> NCIS boss on Ziva exit: 'Prepare yourself for moment in TV history'
Watch a promo for NCIS season 11 below: