SANTA CLARA -- David Akers showed no obvious signs of a pelvis injury while kicking field goals in Wednesday's practice.

Akers' ailment prompted the 49ers to try out two free agents Tuesday. Neither Billy Cundiff nor Nate Kaeding was signed, and Akers' injury isn't believed to be serious.

"David Akers is working through something, and we want to be sure we have a Plan B," coach Jim Harbaugh said.

Late in Sunday's 31-21 win at New Orleans, Akers fell to the turf when his kicking foot got clipped by the Saints' Malcolm Jenkins on a 33-yard field-goal attempt, which Jenkins blocked.

It was the eighth failed field goal in 27 attempts by Akers, who set NFL records last season by making 44 of 52 attempts. Akers is 7 of 14 on attempts of at least 40 yards, including a missed 41-yard try in overtime of the 49ers' Nov. 11 tie with the St. Louis Rams, who host the 49ers on Sunday.

Both Cundiff and Kaeding have seen their careers derailed by playoff struggles. Cundiff missed a last-minute, 32-yard field-goal attempt in last year's AFC Championship loss by the Baltimore Ravens. Kaeding was 8 of 15 on postseason field-goal attempts during his Chargers career, which started in 2004 and ended earlier this season.

  • Rams coach Jeff Fisher called Justin Smith's "grab game" his best move along with NFL sack leader Aldon Smith. Fisher was not accusing Justin Smith of "getting away with murder" by holding linemen, as Giants offensive coordinator Kevin Gilbride did in October.

    "I'm just stating facts and not complaining," Fisher added. "Everybody does it, and Justin does a great job of it. As long as his feet are moving toward the quarterback, it won't be called. It's a legal act. Now if he grabs and pulls backward -- a pull and shoot -- it's not necessarily legal, but it's not something that's going to be called."

  • Tight end Delanie Walker did not practice because of hip and rib injuries he sustained Sunday on a 25-yard reception. Walker did not attribute his increased production to Colin Kaepernick's insertion at quarterback. "Sometimes we have certain plays for certain guys, and last week was my turn," said Walker, who had a season-high three catches for 81 yards.

  • With wide receiver Kyle Williams and running back Kendall Hunter out for the season because of leg injuries, Harbaugh said it was sad to lose "two known friends and trusted agents."

    Brandon Jacobs, LaMichael James and Anthony Dixon were listed by Harbaugh, in that order, as running backs who'll have to fill Hunter's void as Frank Gore's top backup. James, who has been close with Kaepernick since arriving for offseason workouts, said: "If I get the opportunity to play with him, it'll be fun."

  • Alex Smith practiced for the first time without a black, no-contact jersey since his Nov. 11 concussion. Aldon Smith (shoulder) and safety Darcel McBath (concussion) did wear such a jersey and were limited in practice.

  • New to the injury report was safety Donte Whitner (knee) and right tackle Anthony Davis (right pinkie). Both fully practiced, as did Gore (ribs, wrist), cornerback Tarell Brown (knee), safety Dashon Goldson (ribs, calf) and linebacker Patrick Willis (shoulder).

  • Five Rams did not practice: wide receiver Danny Amendola (foot), linebacker Mario Haggan (elbow), running back Steven Jackson (foot), defensive end Robert Quinn (concussion) and center Scott Wells (knee).