A former Liverpool defender crashed with Colmer from Chelsea in Chelsea's first previous season-friendly of the summer after a heavy tackle.
The blues were back in action on Friday evening for the first time since they won the Club World Cup earlier in the summer and recorded in a friendly game in a friendly game just a week from the start of the Premier League season.
It was a comfortable victory for the side of Enzo Maresca, who won 2-0 on Stamford Bridge thanks to Estevao and Joao Pedro. They will also be confronted with Milan on Sunday.
But it didn't come without worry. There were a few familiar faces in the Leverkusen ranks in the competition, including former Brentford goalkeeper Mark Flekken and ex-Southampton and Burnley Man Nathan Tella.
Perhaps the most recognizable for Premier League fans, however, was the former Liverpool defender Jarell Quansah, who left Anfield to join the German outfit for £ 35 million this summer.
And he certainly made himself known to Palmer During the game, he went hard on his teammate of England, which caused an injury to provide and a mini-cuffle.
Palmer had just picked up the ball in midfield, with defender Malo Gusto who played a pass to him, but took a serious touch and an urgent quansah felt the chance to win the ball.
Palmer recovered, however, and first came to the ball, passed him on to try to keep playing. Quansah had already committed.
The defender slid in and Palmer immediately lifted his left foot while shouting the pain, fell to the floor and almost on Quansah while the referee blew their whistle.
While the two players got back on his feet, Quansah tried to continue playing, but Palmer had clearly adopted the incident and Quansah approached from behind and grabbed his back.
The former Liverpool –man took the exception and pushed Palmer while his opponent held himself to his shirt.
The will of Moises Caicedo then came up with the situation, with Quansah, who was recently involved in English squadrons under both Thomas Tuchel and Gareth Southgate, booked about the incident.
It is now only a matter of days until Chelsea plays their first game of the season, with the men of Enzo Maresca to compete against Crystal Palace in their season opener next Sunday.
It is still to be seen how prepared they will be after they have only returned last week for training for the season, but they had no problems sending the Bundesliga two in the capital on Friday.