SANTA CLARA Will Tukuafu is one of three backup defensive linemen on a 49ers team that rarely substitutes along the defensive line.
Last week, however, he had a busy day. Tukuafu was in for three snaps on defense, 11 on special teams and 12 at fullback. In fact, he came close to scoring the 49ers' final touchdown, but a holding penalty by a Jets linebacker prevented him from coming down with what would have been an easy catch in the end zone.
Tukuafu's day was indicative of a team on which even reserves have roles.
Every 49er who was in uniform last week teams can activate 46 players played, the first time that has happened this season.
And it wasn't garbage time.
Everyone from backup quarterback Colin Kaepernick to undrafted rookie tight end Garrett Celek to dime cornerback Perrish Cox had a role in the win.
Nine players, for example, carried the ball on offense, including two wide receivers, Ted Ginn and Mario Manningham, and two quarterbacks, Kaepernick and Alex Smith.
The result is a pile of homework for teams like today's opponent, the Bills, and every other team on the 49ers schedule this year.
"They have different wide receivers in almost every package. It's hard to get a bead on any one thing," Lions coach Jim Schwartz said before Detroit played the 49ers in Week 2.
"A lot of shifts, a lot of motions. It definitely spreads your attention to different places, which I think is what it's all designed to do."
Coach Jim Harbaugh said the "everyone plays" philosophy also promotes team morale when every player feels he has contributed to the cause.
"Whenever possible, when it's possible, when it's earned," Harbaugh said. "The meritocracy of it. The morale of the team. The morale of the individual. Contributing and playing. That can be a good thing, a powerful thing."
The question moving forward is whether Harbaugh and his staff can carve out enough roles for everyone.
Ginn was back in the lineup last week after missing the first three games with an ankle sprain. That gave the 49ers five wide receivers, and only two Michael Crabtree and Manningham caught passes.
Running back Brandon Jacobs is healthy again for the first time since Aug. 18, when he went down with a knee injury. The 49ers already have three running backs Frank Gore, Kendall Hunter and Anthony Dixon on the roster, and Jacobs doesn't play special teams.
Jacobs said this week that he expected to play against the Bills. Harbaugh, however, was noncommittal about the big running back, saying his availability would be a game-time decision.
"We're a pretty fully healthy team right now," Harbaugh said. "And Brandon is saying that he's healthy and ready to go. They're all good options, and we'll see what fits best for us this week."
The 49ers' good health and deep, veteran roster also have meant scant playing time for their rookie class. Top draft picks A.J. Jenkins and LaMichael James, for instance, have yet to set foot on the field this season.
The rookie who has played the most has been sixth-round pick Trenton Robinson. He's gotten into games on special teams.
Harbaugh insisted the rookies still have considerable roles as scout-team players James, for instance, played the part of Bills running back C.J. Spiller in practice this week and that they eventually will be called upon in games.
"I know they want to play, and I think they're demonstrating that on the field," Harbaugh said. "Nobody's hiding. Nobody's trying not to be seen out there on the practice field.
"They're jumping in there, and they're working extremely hard. And that's good; that's what you want."