When the 3-5 St. Louis Rams were preparing to face the San Francisco 49ers on Nov. 11, they were doing so with the understanding that Alex Smith would be the quarterback in the opposing huddle.

Just three weeks later, that same 49ers offense looks a lot different. In place of Smith, the fairly stationary game-manager, the 49ers will start Colin Kaepernick, the mobile and confident second-year player, for a third straight game. The Rams saw plenty of Kaepernick in that week 10 game, so they know what to expect from the quarterback position come Sunday.

They also know what to expect from the rest of the 8-2-1 49ers. The 49ers still boast the second-best defense in the league, allowing just 278.4 yards per game. Not much has changed since they last met: the 49ers have the second-best pass defense and the fourth-best rush defense, allowing just 187.3 passing yards and 91.1 rushing yards per game. They’re allowing just 14.1 points per game, best in the NFL. The Rams scored 24 in San Francisco three weeks ago.

Their defensive front seven is arguably the best in the league. It’s led by the two Smiths, Justin and Aldon. The former’s impact is felt more than seen; the latter’s is definitely seen, to the tune of 16.5 sacks through 11 games. He’s already surpassed the 14 sacks he recorded in 16 games during his rookie season.

Kaepernick gives the offense a dimension that wasn’t present when the teams met last. He’s rushed for over 100 yards in his three games this year, including 66 against the Rams in a game he entered in the second quarter. He’s one of the reasons the 49ers are second in the NFL in rushing with 163.4 yards per game.

Another reason is veteran running back Frank Gore. Gore has 914 yards and is averaging 5.2 yards per rush this year. He’s on his way to another 1,000-yard season, which would be his sixth in eight years as a pro.

Backup running back Kendall Hunter was recently lost for the season, but rookie LaMichael James is a shifty change-of-pace back that will likely step in for Hunter.

In the passing game, the 49ers biggest threat is actually their tight end, Pro Bowler Vernon Davis. Wide receiver Michael Crabtree has also victimized the Rams in recent meetings. The two have combined for 1,054 yards and 10 touchdowns on the year.

Much is still the same, but one noticeable difference from the last time the two teams got together may make a big impact – good or bad – on the teams’ second meeting.