A day after Team Modi took oath, at the BJP headquarters at 11 Ashok Road there were several vacant chambers including that of party chief Rajnath Singh.

The BJP now faces the task of finding someone for the top party post besides filling other gaps caused by around half a dozen office-bearers and four state unit chiefs moving into Narendra Modi's council of ministers.

However, party veterans — LK Advani and Murli Manohar Joshi — are likely to assume the role of mentors, sources said. The Modi government does not have anybody over 75.

If Modi's close aide Amit Shah stays out of government, he may emerge as front runner for the post of BJP president, according to sources. The other name doing the rounds for the job is that of JP Nadda, who like Shah, is also a party general secretary.

Shah, known for his organisational deftness, had resurrected a downcast party in Uttar Pradesh which delivered a record victory of 72 seats for the BJP. Nadda, a Rajya Sabha MP from Himachal Pradesh, is also an organisation man. However, a final decision on who will replace Singh, now the home minister, is likely to be taken after discussions with the RSS top brass.

The BJP, which follows the principle of one-man one-post, is likely to go in for changes in the organisation after a cabinet expansion which is expected to take place only after the short parliament session in June. The defence portfolio, currently held by finance minister Arun Jaitley, is to be allocated to someone else.

While Lok Sabha by-elections will be held Vadodara and Mainpuri, two of the BJP's vacant Rajya Sabha seats would be allotted to Prakash Javadekar and Nirmala Sitharaman, both spokespersons, who have been inducted into the government.

Two general secretaries — Dharmendra Pradhan and Thawarchand Gehlot — and party treasurer Piyush Goyal have also moved into Modi's team.

Though Advani, a former deputy prime minister, was understood to be open to the idea of being Lok Sabha speaker, Sumitra Mahajan is the frontrunner for the post. The other name doing the rounds is those of Karia Munda, who was deputy speaker in the previous regime.