While Henderson missed out on selection, seven of his Ulster team-mates were named in Farrell’s squad.
Backs Jacob Stockdale, Stuart McCloskey, Robert Baloucoune and the uncapped Nathan Doak were included by Farrell, along with forwards Tom Stewart, Tom O’Toole and Nick Timoney.
That more than doubles the tally of three from last year’s tournament, and reflects Ulster’s improved form.
Richie Murphy’s side are third in the United Rugby Championship table and finished top of their Pool in the Challenge Cup to secure a home knockout tie.
Eight more players, including brothers Zac and Bryn Ward, were named in the Ireland XV squad to face England ‘A’ in February.
“We’ve always said it, having guys in green jerseys is hugely positive for Ulster,” Henderson added on Tuesday before the squad was named.
“We want to see as many of our younger guys get exposure to see how a different team works, how international coaches work and get experience at that top-end level with the pressure.
“I think we have a handful of guys who are excelling with Ulster and would continue to excel at international level.”
Listen to the Ireland Rugby Social podcast with Conor Murray and Jacob Stockdale on BBC Sounds.
