I got this off of CBS sports which has a great blog for playoff scenarios and tiebrakers and how teams can clinch and what not. But here is the official scenario for the Steelers to not just clinch a playoff spot this weekend but also clinch the AFC North and possibly a first round bye as well...

PIT clinches a playoff berth with
1) a win (vs. NYJ).
2) a JAX win and a SD loss.
3) a JAX win and a KC loss.

Reasoning: An 11th win would put the Steelers out of reach of all AFC Wild Card contenders except for NYJ. (In this scenario, we're assuming that BAL ends up taking the AFC North, so they would not be in the Wild Card race.)

If IND wins the AFC South, PIT could lose a tie at 10-6 for the final Wild Card spot with JAX, because the tiebreak would come down to strength of victory. A JAX win over IND guarantees that JAX will be the AFC South champion if they finish 10-6, eliminating this possibility.

A three-way tie between PIT, NYJ, and SD at 10-6 would come down to strength of victory and is the only remaining scenario that could cause PIT to miss the playoffs. If SD were to advance first, NYJ would take the remaining Wild Card spot based on the head-to-head win over PIT we are assuming in this scenario.

There are two ways to ensure that SD does not end up in this three-way tie at 10-6. First, if SD loses, the Chargers will not be able to finish 10-6. Second, if KC loses, the Chiefs will be able to finish 10-6 at best, and SD will have clinched the common-games tiebreaker with KC, meaning that SD will be the AFC West champion if both teams finish 10-6, not part of the Wild Card race.

Now, the scenarios taking tonight's BAL@HOU game into account:

If BAL loses to HOU on Monday night:
PIT clinches the AFC North division with
1) a win and a BAL loss.

Reasoning: PIT could finish at worst 11-5; BAL could finish at best 10-6.

If BAL loses to HOU on Monday night:
PIT clinches the AFC North division and a first-round bye with
1) a win and a BAL loss and a JAX loss.

Reasoning: PIT's worst possible record against the AFC would be 9-3. NYJ could equal that by winning out and would therefore need to lose in order to guarantee PIT the at least the #2 seed. KC's best possible AFC record is 7-5, so they would not be able to catch PIT.