Detroit Lions vs. San Francisco 49ers: Key Matchups That Will Decide NFC Clash

The San Francisco 49ers stopped one high-potent offense in Week 1. They'll look to do the same against another high-potent offense in the Detroit Lions on Sunday Night football. The teams, both 1-0, are contenders in the NFC. Last year's matchup had the Niners winning 25-19, a game that was marred by "handshake-gate" where Jim Harbaugh's postgame exuberance led to a tussle between him and Jim Schwartz and the rest of the players on the field.

While that certainly looms over the game, the contest will be decided on the field. These are two good teams with playoff aspirations. What are the key matchups that will come to define this game? Read below to find out. 

Alex Smith vs. Matthew Stafford

Last week, it was Alex Smith against Aaron Rodgers. This week, Smith faces Matthew Stafford. Smith threw for 211 yards and two scores against the Packers in Week 1. The Packers defense has long been suspect, but they did put up a dominating performance Thursday night against the Bears.

Matthew Stafford, on the other hand, had a bit of a rougher time in Week 1, throwing for 355 yards and three interceptions against a shaky Rams defense. The 49ers defense could give him more trouble.

It may be football cliche, but this game will be dictated by the two quarterbacks. If Smith continues his solid, mistake-free play, the 49ers should come out on top. If Stafford can rebound from his rough opener and limit the turnovers, the Lions could pull this out. 

Calvin Johnson vs. 49ers Secondary

Calvin Johnson is one of the best receivers in football, and it's always a chore to stop him. Last week, "Megatron" had six catches for 111 yards.

The 49ers secondary has a quandary. If they decide to double-team him, that will leave the other talented Detroit skill players open. If they decide not to double-team him, he could have a monster game.

What is more likely is that the 49ers do some sort of "bracket" coverage, where they keep safety help over the top. They will also be very physical with him on the line. One corner probably won't get the assignment; it will be a team effort between Chris Culliver, Carlos Rogers and Tarrell Brown.

Stopping Johnson is impossible—limiting him is the name of the game. If he has a huge game, which he is certainly capable of, the Lions could put up 40-plus points and win handily. One of the big keys to stopping Johnson is putting pressure on Stafford. 

Detroit Offensive Line vs. San Francisco Defensive Line

The 49ers have one of the best defensive lines in football. It is difficult to stop Aldon and Justin Smith. The Lions, as Andrew Garda writes, will have no choice but to add extra blockers:

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So the Lions can do something else aside from just read the defense right and throw some outlet passes. 

They can bring in extra blockers as they did against the Rams.

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Read the rest of Andrew's excellent article for more analysis. If the Lions can combine quick strike passes with keeping in an extra running back or tight end, they should have enough time to get the offense moving. If not, and the 49ers are able to swarm all over Stafford, it could be a long day.

Games are decided in the trenches, and the winner of this matchup will go a long way towards deciding the winner.