A tactical consideration for 49ers' defense

SAN FRANCISCO -- The Pittsburgh Steelers use three tight ends with one running back more frequently than any NFL team.

That might not excite you, but it has caught the attention of the San Francisco 49ers' defensive coordinator. Vic Fangio pointed to that personnel grouping during his weekly media session as evidence of the Steelers' versatility on offense.

One consideration for San Francisco: The 49ers' base defense would likely remain on the field against three tight ends, meaning the team's leader in sacks, Aldon Smith, would not be on the field. This would not matter much if the Steelers chose to run the ball from these personnel groupings. They have thrown about one-third of the time from this personnel, however, and with quarterback Ben Roethlisberger playing through an ankle injury, this grouping could provide flexibility in protection.

It is one thing to watch for beyond the five we discussed a bit earlier.

"They do like to play a lot of three-wide receiver sets on the early downs," Fangio told reporters. "They’ll also sprinkle in some four-wide receiver sets and even occasionally there'll be five wide receivers out there. So, they will dictate what type of game it is, but they’ll also, even while they’re doing that, play their two tight ends. They even have a personnel group that they play about 20 percent of the time, three tight ends with one back and one receiver. ... They've probably got the best group of blocking tight ends in the league."

The Steelers had run a league-high 20 plays using five wide receivers entering Week 15, according to ESPN Stats & Information. That was four times as many as any team in the NFL. They ranked among the top five in snaps with four wideouts. Throw in those "13" personnel groupings with one back and three tight ends, and Fangio was right about the Steelers forcing defenses to account for multiple looks.