SANTA CLARA -- Brandon Jacobs and Mario Manningham have begun their 49ers tenures in vastly different fashion since leaving behind the New York Giants' championship throne.
Jacobs hasn't debuted in a 49ers uniform, and while a knee injury has been the chief culprit, he attempted Thursday to squash any speculation that he's unhappy.
Minutes earlier, Manningham merrily spoke about his expanding role, even regaling the media with how he was groomed as a child to make sideline catches on his small front yard in the Ohio projects.
Aside from their past employer, Jacobs and Manningham do have something else in common: they clearly want the 49ers (4-1) to press forward with a victory Sunday against the Giants (3-2).
Jacobs, especially, wants to move onward, and that meant addressing a USA Today report from Wednesday in which he expressed frustration over not knowing why he hasn't been activated for a game despite allegedly being healthy.
Jacobs said he has spoken with coach Jim Harbaugh "a couple times the last couple days" about his status.
"We ironed it out," Jacobs said. "I understand where he's coming from. He understands where me ... with the competitive nature as an athlete of wanting to get out and help the team win."
Jacobs returned to practice two weeks ago after sustaining an injury to his left knee in an Aug. 18 exhibition at Houston. Although he proclaimed himself fully healthy last week, he remained idle
Jacobs now says he's positioned for a "unique opportunity" where he doesn't have to risk playing hurt, not when the 49ers already lead the league in rushing behind the 1-2 punch of Frank Gore and Kendall Hunter.
Added Jacobs: "Right now, could I go out and play? Yes. Would it be smart? No."
Jacobs, the Giants' all-time leader in rushing touchdowns, showed prowess as a short-yardage specialist in the 49ers' exhibition season before getting hurt. He's not the only high-profile running back on the bench. Second-round draft pick LaMichael James also has been inactive each game.
Manningham, meanwhile, is showing more and more why the 49ers poached him from the Giants. He's the only 49er to have at least three catches each game, and he scored his first touchdown of the season Sunday when he showed off his swift route running.
"He's got a great feel for the game, understands how to get open and has extremely good feet," offensive coordinator Greg Roman said.
Known best for a sensational sideline grab that sparked the Giants' Super Bowl-winning drive, Manningham has continued to show an innate ability to make boundary catches, a skill he started honing
"Our yard wasn't very big, and we always played that you had to get two feet in bounds," Manningham said. "In 6-on-6, you were a little cluttered, so you had to make it work."
Instead of Randy Moss emerging as a starting receiver opposite Michael Crabtree, it has been Manningham, who ranks third among 49ers with 19 receptions for 186 yards. Manningham said he expects to break a short pass for a long gain "before the year's over."
Manningham has been helping the 49ers' defensive backs scout the Giants' defensive tendencies.
On the flip side, the 49ers aren't intensely asking Manningham and Jacobs to help crack the Giants' offensive codes, according to 49ers defensive coordinator Vic Fangio.
"We kind of know them," Fangio said of the Giants. "We played them twice last year. They're almost like a division opponent that hasn't changed its coaching staff or personnel much."
Not much, other than two notable castaways who now reside on the 49ers.