Washington (CNN) John Kelly is expected to resign as White House chief of staff in the coming days, two sources familiar with the situation unfolding in the West Wing tell CNN.

Seventeen months in, Kelly and President Donald Trump have reached a stalemate in their relationship and it is no longer seen as tenable by either party. Though Trump asked Kelly over the summer to stay on as chief of staff for two more years , the two have stopped speaking in recent days.

Trump is actively discussing a replacement plan, though a person involved in the process said nothing is final right now and ultimately nothing is final until Trump announces it. Potential replacements include Nick Ayers, Vice President Mike Pence's chief of staff, who is still seen as a leading contender

Kelly has been on the verge of resigning or being fired before, only to bounce back every time. But aides feel the relationship can't be salvaged this time. Trump is becoming increasingly concerned about Democrats taking over the House in January, and has privately said he needs someone else to help shape the last two years of his first term, which he predicts will be politically focused. He has complained repeatedly that Kelly is not politically savvy.

The expected departure would end a tumultuous tenure for Kelly, who was brought on to bring order to the White House but whose time as chief of staff has often been marked by the same infighting and controversy that has largely defined Trump's presidency from its beginning. Many of the storms in which Kelly became embroiled were by his own making.