Delhomme injured his right ankle in last week's loss at Tampa Bay and missed practice this week. He is inactive Sunday, making rookie Colt McCoy the No. 2 quarterback against the Chiefs.
The more mobile Wallace, who spent seven seasons with Seattle, is making his 15th career start. He went 5-9 as a starter for the Seahawks.
Delhomme threw two interceptions, including a game-swinging one at the end of the first half, in his debut with Cleveland last week. The Browns signed him as a free agent in March.