EAST RUTHERFORD, N.J. – The Giants, who gained a running back but lost a linebacker during the week, today lost a running back but added a linebacker.
The team announced that Peyton Hillis, the team's third-leading rusher, was placed on injured reserve with a concussion, his second in as many seasons. His roster spot was taken by linebacker Justin Anderson, who was signed off the practice squad.
The Giants will host the San Francisco 49ers tomorrow. This week, they welcomed back running back Rashad Jennings, who missed the previous four games with a knee injury. Jacquian Williams, the Giants' leading tackler, will be sidelined for the game vs. San Francisco with a concussion he sustained last week in Seattle.
Hillis, a seven-year pro, joined the Giants on Oct. 16, 2013. Last year, he played in seven games and rushed for 247 yards and two touchdowns and caught 13 passes for 96 yards. He suffered a concussion in a loss to Seattle on Dec. 15 and missed the game the following week in Detroit.
This year, Hillis sat out much of training camp and the preseason with an ankle injury. But he played in each of the first nine regular-season games before again suffering a concussion last week, in another game against the Seahawks. Hillis finished the season with 26 rushing attempts for 115 yards, a 4.4-yard average, and 10 receptions for 87 yards.
Anderson, 6-3 and 232 pounds, was originally signed as a rookie free agent by the Giants on May 12 from Louisiana-Lafayette. He was waived on Aug. 26 and signed to the practice squad on Oct. 29. Anderson had three tackles and a forced fumble in the preseason.
He led the Ragin' Cajuns in tackles in both 2012 and 2013, and finished his career with 294 tackles (166 solo) and 3.5 sacks.
Keep an eye on these 5 players as the Giants face the 49ers on Sunday

RB Rashad Jennings Jennings is listed as probable to make his return on Sunday after missing the past four games with a knee injury. In five games this season, Jennings has 91 rushing attempts for 396 yards and two touchdowns, in addition to 11 catches for 109 yards. "Anxious is a good word, anxious to get back on the field," Jennings said. "This is my livelihood, this is what I do as a profession. It's my job, it's my business, it's what I love to do. When you're unable to perform on the field, you feel like something's stripped away from you, but it was a time where I think on and off the field I was able to recalibrate some things and come back to the game with a stronger perspective.">> TEAM ANTICIPATES OFFENSIVE BOOST WITH JENNINGS' RETURN

LB Devon Kennard In addition to Mark Herzlich and Spencer Paysinger, the rookie Kennard will be used in the linebacker rotation to compensate for Jacquian Williams, who is out with a concussion. After allowing 350 rushing yards to quarterback Russell Wilson and the Seattle Seahawks last week, the Giants' entire front seven will have to be on their game against a similar threat in Colin Kaepernick and the San Francisco 49ers. "I feel comfortable," Kennard said. "I am excited for the opportunity and it is something I have been working towards all camp and everything and all this season so far. I feel ready for the opportunity."

WR Odell Beckham Jr. A bright spot in the Giants' current four-game losing streak has been the emergence of Beckham, the team's rookie first-round draft pick. Beckham is leading the league in receiving yards over the last two weeks, including 108 against Seattle's vaunted secondary. "That's another one of those things where it's great, but without winning, it's just kind of like, 'OK,'" Beckham said. "That's just one of those things that I just want to keep continuing to improve and do more, do more for the team.">> THE BECKHAM JR. REPORT: EXCLUSIVE GIANTS.COM INTERVIEW

S Stevie Brown After Quintin Demps replaced him as a starter in Week 4, Brown has seen his number of snaps gradually increase back up over the last few weeks and could be a factor in more three-safety looks. "We're trying to get both guys integrated," defensive coordinator Perry Fewell said. "We'll try to use a little bit of the three-safety package a little bit. Nothing out of the ordinary."

DE Robert Ayers Jr. Ayers has registered a sack in back-to-back games, bringing his season total to a team-high four. However, in spite of Ayers' efforts, the defense has dropped to last in the NFL in yards allowed per game. Now Ayers and the Giants will try to crawl out. "We're at the 32nd spot right now," Fewell said. "We have seven games to crawl out of that spot. We'll crawl out."