Schalke coach Felix Magath has sent American midfielder Jermaine Jones and two others to the reserve team because he was unhappy with their effort and commitment.
The move came three days after Schalke's 5-0 loss at Kaiserslautern. Schalke's reserve side competes in a fourth-tier league.
"I did not like the attitude of Jermaine Jones in matches, and I did not like the attitude in practice of the other two," Magath said Tuesday.
The other players sent to the reserves are Ghana defender Hans Sarpei and midfielder Alexander Baumjohann.
Jones, who made his U.S. national team debut in October, had been dropped from Schalke's squad for one game earlier this season but returned to the starting lineup.
Schalke's loss at Kaiserslautern came three days after Magath's team had advanced to the second round of the Champions League.
After the loss, Magath said changes were necessary.
He has already cut the players' Christmas vacation to five days and has been starting morning training one hour earlier, at 9 a.m.
The loss in Kaiserslautern left Schalke (3-7-4) in 15th place with 13 points, only three points more than last-place Borussia Moenchengladbach (2-8-4), the team of American midfielder Michael Bradley. Schalke was runner-up in the league last season, in Magath's first year at the club.
Magath, who has won Bundesliga titles with Bayern Munich and Wolfsburg, was hired by Schalke in an attempt to win the club's first championship in five decades.
"I had and still have much higher expectations from Felix Magath than avoiding relegation," club chief Clemens Toennies told Bild newspaper.
Schalke is home Saturday against Bayern Munich.