Out of a possible 121 combined starts, Vikings defenders have missed only eight because of injuries this season.

That will climb to 10 out of a possible 132 after nose tackle Linval Joseph (foot) and safety Andrew Sendejo (knee) were ruled out for Sunday's game against Seattle at TCF Bank Stadium. However, the team still enjoys relatively good health, which has contributed to its No. 2 ranking as a scoring defense (17.6).

Depth also has played a significant role. Because the missed games have been spread throughout the lineup over the past eight games, the Vikings' 11 current defensive starters have only played one game together: the 30-13 loss to the Packers two weeks ago.

Beginning Week 4, the Vikings have had at least one defensive starter sit out every game except the Packers game. The Nov. 8 win over the Rams was the only time two defensive starters (Sharrif Floyd and Eric Kendricks) missed the same game.

There were no injuries in Weeks 1-3, but the starting middle linebacker was Gerald Hodges, who was traded to San Francisco after the fourth game.

Sunday, Floyd will move to nose tackle and Tom Johnson will start at Floyd's three-technique tackle spot for the fifth time this season. He started in the three games Floyd missed and the first game after Floyd's return. The Vikings went 4-0 in those games.

"Tom is a good player," Vikings coach Mike Zimmer said. "He's a veteran guy. He's smart. He knows the system we're trying to run. He knows what we're trying to get accomplished. But it's always good to have multiple guys and have good depth at really all the positions."

Coach Joseph?

Joseph was in the locker room Friday with his right big toe heavily taped as he spoke to reporters about missing his first game of the season.

"Of course it's going to be frustrating," he said. "But I'm just glad I can still support my team and go out there and just use my eyes and be a coach."

Joseph wouldn't venture a guess on when he thinks he'll return.

"Right now, I'm doing the best I can do," said Joseph, who didn't practice all week. "I can't wait to get back when the time is right."

Exum likely to start

The Vikings won't be at full strength at safety, but the good news is free safety Harrison Smith will return after missing last week's game because of a knee injury. Smith and linebacker Anthony Barr (hand/groin) are questionable but expected to play after limited participation in each practice this week.

With Sendejo out, the Vikings are expected to start Antone Exum at strong safety. He made his NFL starting debut last week at free safety in place of Smith.

Smith said Exum shouldn't have any problems switching from free safety to strong.

"We kind of say they're mirrored positions," Smith said. "There are little things about both positions that are different. But if you know one, you should know the other."

Bevell 'unpredictable'

After struggling earlier this season, Seattle's offense appears to have turned a corner, as evidenced by last week's 39-point, 436-yard effort in last week's win over Pittsburgh.

Offensive coordinator Darrell Bevell, who was vilified for his decision to throw the ball on the goal line in the closing seconds of Seattle's Super Bowl loss in February, has Seattle averaging 5.91 yards per play. That would be a franchise record if sustained over the entire season.

"I think he does a really good job with the personnel groups, the formations out of them, the differences from week to week," Zimmer said of Bevell. "They do, really, a lot of different things. They're unpredictable in their calls, so it makes it tougher."

Waynes will return

Two players were listed as probable with full participation all week: safety Robert Blanton (ankle) and cornerback Trae Waynes (ankle), who missed last week's game because of the injury.