TOKYO, Aug 31 (Reuters) - Japanese Prime Minister Yoshihide Suga is considering a reshuffle of executive posts in his ruling party that would involve the replacement of his close associate and secretary general Toshihiro Nikai, the Nikkei newspaper said on Tuesday. The move could come before the Liberal Democratic Party (LDP) votes on its leadership on Sept. 29, the Nikkei reported, without citing sources. The winner of that party poll will guide the party through a general election expected as early as in October. read more In a meeting with Suga, Nikai told the prime minister he would concede to stepping down, the Nikkei said. The offices of Suga and Nikai were not immediately available for comment. Nikai, who has held the key LDP post for five years, has repeatedly voiced his support for the prime minister. Former foreign minister Fumio Kishida has said he would run for the LDP leadership race.