The head of the Polish Presidential Chancellery, Aleksander Szczyglo, said on Monday that he would accept the post of defense minister at the proposal of Prime Minister Jaroslaw Kaczynski.
Szczyglo told TVN24 television that he might be nominated as defense chief in several days and that the president had agreed to let him leave his current post.
Polish government spokesman Jan Dziedziczak told the PAP news agency that Szczyglo's nomination might be made on Wednesday.
Szczyglo was appointed the head of the Polish Presidential Chancellery last August from the post of deputy defense minister.
Earlier on Wednesday, the Polish prime minister accepted the resignation of Defense Minister Radoslaw Sikorski.
Sikorski was reported to quit amid a dispute with Kaczynski and his brother, President Lech Kaczynski.
Polish media reported over the weekend that Sikorski could lose his post after having been criticized by the Kaczynski brothers for his handling of negotiations with the United States over the stationing of a U.S. missile defense system in Poland.
Tensions have also been fueled by Sikorski's open opposition to a Kaczynski associate, Antoni Macierewicz, who heads the military counter-intelligence service, reports said.
At his farewell press conference, Sikorski confirmed he had asked the prime minister to dismiss Macierewicz, but did not say if the matter was behind his own resignation.