The Bears on Monday placed running back Jacquizz Rodgers on injured reserve with a broken arm he sustained in the second half of Sunday's 18-17 win over the Chiefs.
Running back Antone Smith appeared in 59 games over five seasons with Atlanta.
Rodgers signed with the Bears March 31 after spending his first four NFL seasons with the Falcons. The 5-6, 196-pounder appeared in the first five games, rushing for 41 yards on 14 carries, catching one pass for 10 yards and recording three special-teams tackles.
"He's a guy who kind of surpassed probably our expectations and contributed on the field, whether it was on offense or in the kicking game," said coach John Fox. "He's a guy that will be missed, but over time he'll get better and we'll get back in the future."
The Bears acted quickly to replace Rodgers, signing his former Falcons teammate, running back Antone Smith. The 5-9, 192-pounder appeared in 59 games over five seasons with Atlanta from 2009-14, rushing for 266 yards and four TDs on 29 carries and catching 15 passes for 232 yards and three TDs.
Smith entered the league with the Lions in 2009 as an undrafted free agent out of Florida State. He also had stints with the Vikings and Texans before making his NFL debut with the Falcons as a rookie.
In Atlanta's first six games last year, Smith had rushes of 48 and 38 yards and receptions of 74, 54 and 41 yards—on just 23 touches. In Week 11, he was lost for the season with a broken leg he suffered while covering a punt against the Panthers.
It's unclear where Smith will fit on the Bears' depth chart at running back. Rodgers was listed second behind starter Kyle Long and ahead of rookie Jeremy Langford and second-year pro Ka'Deem Carey.
Langford has had just three carries in the last three games after rushing for 21 yards on six attempts in a Week 2 loss to the Cardinals, while Carey has played in only one game this season.
"It affects everybody," Fox said of losing Rodgers. "We'll take a look at Antone. He's going to be new to us. Ka'Deem Carey's been on the roster as well as Jeremy Langford. Guys that we have faith in putting out there, we've done some of that already. So it's back to our normal deal, next-man-up, and we feel confident they'll step up in a good way."
Fox did not provide an update on the injuries that linebacker Shea McClellin (knee) and cornerback Terrance Mitchell (hamstring) suffered against the Chiefs. Asked if McClellin would miss the rest of the season, Fox said: "At this point it's not been determined. We'll update you on Wednesday."