Glenn Whelan will not return to the Hearts squad on Sunday despite Daniel Stendel facing the "most difficult moment" of his managerial career.
The 35-year-old Republic of Ireland midfielder was dropped on Thursday as Hearts stayed bottom of the table after a 2-0 derby defeat by Hibernian.
It was Hearts' fifth consecutive loss - and fourth under Stendel - but Whelan will not feature against Aberdeen.
"I think he will not be in," Stendel said.
"We didn't win, but I think we improved in a lot of things and, in the squad for Sunday, we trust the players who played yesterday."
Whelan signed a one-year contract in the summer after being released by promoted Aston Villa and was hopeful of regular first-team action as he seeks a place in his national squad for the Euro 2020 play-offs.
He has made 17 appearances this season but has been dropped after three starts and one substitute appearance under Stendel.
Asked if the Irishman would return to the squad after January's winter break, the German said: "We will see. We are talking with him, but at the moment I changed the squad a little from last Saturday."
Stendel was sacked after less than a year with Hannover 96 and then axed in October, 18 months into his two-year Barnsley contact, despite winning promotion to the Championship in England.
However, the German suggested: "This is the most difficult moment for me in my career as a coach."
Hearts lie three points behind Hamilton Academical in the Scottish Premiership and without a point under their new manager, who hinted of personnel changes during the January transfer window.
"When you take things and they are not easy then you learn the most," he added. "You can improve the most from a situation like this.
"For me, this is a new moment and I can only say I like to improve myself and I will do it. What I need are players who want to do it also."