Despite constant assertions by players and coaches that the game plan doesn't change because of injuries, offensive coordinator Bruce Arians admitted he has had to change his play-calling because of the amount of injuries on offense.

The Steelers will get Pro Bowl running back Willie Parker back against the San Diego Chargers after he has missed five of the past six games with knee and shoulder injuries. And it appears quarterback Ben Roethlisberger, who has a sore right shoulder, will go through a full week of practice for one of the few times in the past month.

But they are still without left tackle Marvel Smith, who has missed the past four games with a back injury, and tight end Heath Miller, who will miss his second game in a row with a high-ankle sprain. And they lost guard Kendall Simmons and backup running back Rashard Mendenhall to season-ending injuries.

"Sure," Arians said yesterday when asked if injuries have limited his ability to call certain plays. "You do different things for different guys. You tailor the game plan to who's playing and give them a chance to win."

Roethlisberger and coach Mike Tomlin have each said in the past two weeks that the offense, which ranks 26th in the NFL, has performed at a subpar level. Roethlisberger's passer-rating of 76.1 ranks 25th in the league and he has thrown eight interceptions and just one touchdown in the past three games.

Even the running game has struggled, gaining just 55 yards against the Indianapolis Colts, which had one of the worst run defenses in the league. That's why Arians blanched when asked if the offense has developed an identity.

"There's about four or five identities, as far as who's lining up," he said. "We haven't been lining up with the same guys. It's hard."

Injuries

Outside linebacker LaMarr Woodley, who did not play against the Colts because of a calf injury, returned to practice and is expected to start against the Chargers. Woodley is second on the team, behind James Harrison, with 9.5 sacks.

"I thought he looked good," Tomlin said. "We'll see how he feels in the morning.

Smith (back) did not practice and is not expected to play. Asked if Smith is in danger of not returning this season, Tomlin said, "Not at this point, no."

Kick coverage turnaround

Despite having the league's No. 1 defense, the Steelers' most consistent unit might be their kick and punt coverage teams.

One year after those units cost them several games and ranked among the worst in the league, the Steelers rank second in kick coverage (20.2 yards) and third (5.0) in punt coverage in the NFL. What's more, they haven't allowed any return longer than 40 yards.

They will need some of that against the Chargers' dual returner, Darren Sproles, who is fourth in the AFC in both punt (11.4 yards) and kick (27.2) returns. Sproles had a 103-yard kick return for touchdown against Denver.

"We have a little continuity; it is year two, I think you have to acknowledge that," Tomlin said when asked to explain the difference in the coverage units. "Also, we've got some continuity with the core players. Guys like Anthony Madison are in the second year in the coverage units, Lawrence Timmons is in his second year in the coverage units. They are making plays for us. The addition of Keyaron Fox is big. Young guys like Pat Bailey kicking in.

"It has been a winning edge for us and it needs to be a winning edge for us this weekend because like I said earlier, San Diego is very good and it starts with Sproles as a return man, both punts and kicks."

West Coast jet lag

How difficult is it for West Coast teams to play in the Eastern time zone?

The Chargers are one of five NFL teams from the Pacific Standard Time zone who are a combined 0-12 in games in the East this season.

The Chargers (0-2) join the Seattle Seahawks (0-4), Arizona Cardinals (0-3), Oakland Raiders (0-2) and San Francisco 49ers (0-1). The Cardinals were included in the group because, even though the state of Arizona is always in the Mountain Standard Time zone, it operates on Pacific Daylight Time seven months out of the year.

"Like everyone, you have mixed results when you go across the country and play good football teams," Chargers coach Norv Turner said. "It is a schedule that we have used for a long time and it works. It is a little different when you are playing a 1 o'clock game, obviously, because your body is telling you it is 10 in the morning. If it is a 4:15 [p.m.] game, I think it gives you time to adjust."