SANTA CLARA, Calif. (AP) Shaun Draughn knows something about making quick adjustments.

The San Francisco 49ers became his eighth team in the NFL after he signed a deal on Monday.

Draughn and fellow running back Pierre Thomas, who was signed Tuesday, were brought in after Reggie Bush went on injured reserve and with questions remaining regarding the health of Carlos Hyde, who missed practice Thursday, and rookie Mike Davis, who broke his hand in the loss to the St. Louis Rams last Sunday.

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They'll be expected to give a struggling 49ers offense a boost. The 49ers rank last in total offense and scoring offense and next-to-last in pass offense.

Their one saving grace is the ability to run the ball, though the Rams held San Francisco to 38 yards on the ground.

Kendall Gaskins was promoted to the active roster for the Rams game and made his NFL debut. Offensive coordinator Geep Chryst expects to have three running backs available for Sunday's game against the Atlanta Falcons.

''Our charge is still get the running game going, to get the play-action going and mix that in with some passes,'' Chryst said. ''We have to let it play out.''

Thomas, the New Orleans Saints' all-time leader in pass receptions by a running back, played his final game with the Saints last December. The 49ers had him in for a workout early in the season.

Thomas spent eight years with the Saints, where he's fourth all-time with 3,745 rushing yards.

Draughn last played in a game Oct. 18. The Cleveland Browns released him two days later. He'd been waiting by the phone ever since.

He got the call Sunday night.

''I was working out, spending time with my wife and kids,'' Draughn said. ''I was hoping and praying.''

Draughn, signed as an undrafted free agent in 2011, ran for 233 of his 264 career yards with the Kansas City Chiefs in 2012. He also has 26 career receptions for 159 yards, and has returned kicks.

''I'm trying to catch up,'' he said. ''This is my eighth team and I'm correlating everything I've learned before to how it relates to now. I'm putting in the time and trying to learn it all.''

Draughn was recruited to North Carolina as a safety, playing a year on defense before making the switch to running back. He's been making adjustments all his life.

''I'm decent,'' he said. ''I'm just a guy who prepares like a starter and who will be ready when his name is called.''

NOTES: WR Anquan Boldin and CB Kenneth Acker also sat out Thursday's practice. ... CB Keith Reaser participated in practice with a heavily taped ankle. ... LB NaVorro Bowman continues to be limited in practice.

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