The league's match review panel handed down the sanction on Monday following the German's red card late in a 3-0 win over Melbourne Victory last Friday.

Baumjohann was sent off for lashing out at Leigh Broxham after a challenge by the Victory defender in stoppage time at AAMI Park.

Broxham, already on a yellow card, was also given his marching orders for the tackle on Baumjohann.

After analysing footage of the incident on Tuesday, the club decided not to lodge an appeal and the 33-year-old will now miss this weekend's home match against Brisbane Roar.

He'll also be unavailable for the Sydney derby against former club Western Sydney Wanderers.

In other news on Tuesday, the Sky Blues confirmed midfielder Luke Brattan had signed a new deal with the club.

Brattan, who joined Sydney in the off-season, has committed until at least the end of the 2021-22 campaign.

The 29-year-old, who has previously played with the Roar and Melbourne City, has made 13 appearances for Sydney this season.

"Luke has been outstanding since arriving here and I'm delighted he is staying with us," Sydney coach Steve Corica said.

"We are very fortunate to have him in our outstanding squad and this gives me increased confidence we can continue to perform for the rest of this season and beyond."

Australian Associated Press