The RFU rules for international call-up state that those not playing in England will be barred except "in extraordinary circumstances".
British media reports in March suggested that Premiership clubs could block the move to select Underhill, who shifted base to Wales also for educational commitments.
Asked if there had been a clear directive from the RFU regarding the eligibility of the former England under-18 player, Jones said: "yes and no".
"'Yes' is that I don't think that his position has changed, and the 'no' is that we still need to investigate. We'll just wait and see," he told British media.
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Jones added that Fiji-born Nathan Hughes, who has completed his three-year residency to be eligible for England selection, will most likely operate at blindside flank.
"I'll probably look at him more as a six than an eight, but certainly he's a guy that's got something that you can coach," Jones added.
"His ball-carrying is something that you can't coach, which gives him a head start and if he can pick up in his other areas then he is going to be a pretty handy player."
England host South Africa, Fiji, Argentina and Australia at Twickenham in the autumn internationals in November and early December.
(Reporting by Nivedita Shankar in Bengaluru; editing by Sudipto Ganguly)
