KANSAS CITY, Mo. -- The Kansas City Chiefs acknowledged they would go through some growing pains with rookie De'Anthony Thomas as their punt returner. That has come to pass.

Thomas has made some decisions to both return punts and let them bounce that have cost the Chiefs significant yardage. Field position is most important for the Chiefs, who don't get many big offensive plays.

The Chiefs became so frustrated with Thomas during last week's loss to the Oakland Raiders that he was replaced as punt returner by Frankie Hammond Jr. But special teams coordinator Dave Toub said Thomas will go back to being the main punt returner in Sunday night's game against the Denver Broncos at Arrowhead Stadium.

"There's a learning curve with punt returners," said Toub, who with the Chicago Bears coached one of the game's all-time great kick returners in Devin Hester. "I went through the same thing with Devin Hester. He's got to learn to go get the ball, the short ones. He has to understand the fair catch is a weapon. That's what he's not doing yet. We've talked about it and he's going to continue to get better at it.

"He wants to return everything, which is a great trait to have. But sometimes you've just got to say, 'The coverage is there, the punt is there, I've got to use the fair catch.' That's where we are with him."

Thomas' biggest error against the Raiders was taking a 12-yard loss on a return that forced the Chiefs to begin a drive on their 5. Thomas is world-class fast when in the open field but he retreated in an effort to get outside on this particular play.

The Raiders wouldn't let him.

"We wanted him to field that ball the way he did," Toub said. "What he has to learn is that you can't run around NFL players. The NFL players are really, really fast. Sometimes you have to just catch the ball, get the ball in your hands and get five yards and just save the ball from bouncing and we'll play on from there. That's part of his learning experience and he'll get better and better."