Here are some match-ups to watch in tonight's game at Washington.

ROLB James Harrison vs. LT Chris Samuels

Samuels was replaced in the Redskins 25-17 win over Detroit in Week 8 by Stephon Heyer, and the results were disastrous. It was poor enough of a performance to force Samuels, who has loose cartilage in his knee, back into the lineup Monday night. With a bum knee and a back-up ill-prepared to face one of the league’s best pass rushers – Harrison – it’s a good bet Steelers defensive coordinator Dick LeBeau will go at Samuels all game.

Harrison is third in the NFL with 7.5 sacks. He also has seven sacks as a starter in three career Monday night games. While he was kept out of that stat last week against the Giants, he provided relentless pressure, a characteristic that has become his trademark. He plays with outstanding balance and leverage, which unlock his explosiveness. That makes him a dangerous pass rusher going straight at the tackle or moving around him. Harrison will be the key to disrupting the Redskins’ precision offense.

DEs Aaron Smith and Brett Keisel and NT Casey Hampton vs. RB Clinton Portis

Portis, the NFL’s leading rusher, is poised to crack 1,000 yards for the season in Week 9 because of his vision. While the Redskins don’t employ a full zone-blocking scheme, Portis has a fantastic ability to cut back into unprotected running lanes. The Redskins run a lot of counters and rely on Portis to see the play developing and find that cut-back lane.

Smith, Keisel and Hampton are critical in stopping Portis. They have to maintain gap discipline, and not allow Portis to square his shoulders at the second level. If they can force him to bounce outside the line, the Steelers’ physical linebackers can get to him. If not, the Redskins balanced offense will get comfortable and control the tempo of the game.

WRs Santonio Holmes and Nate Washington vs. CBs Leigh Torrence and Carlos Rogers

The strength of the Redskins’ cornerbacks is in their press coverage. That’s also an area of weakness for Washington and Holmes. QB Ben Roethlisberger can attribute at least a few of the 23 sacks he’s taken this year to his receivers’ struggles in breaking press coverage and getting separation. Expect Torrence – starting for injured Shawn Springs (calf) – and Rogers to get in Holmes’ and Washington’s faces all game.

It’s a risk, though, considering the deep speed of the Steelers receivers. Roethlisberger and Washington have hooked up for three pass plays of 48 yards or more in the past three games. Much of the game plan will be to exploit WR Hines Ward and TE Heath Miller’s abilities in the middle of the field, but if Washington or Holmes and break the press and get down the numbers, the Steelers will look to connect on a big play or two.

RB Mewelde Moore vs. LB London Fletcher

While starter Willie Parker will be back this week and likely will have the bulk of the carries, Moore has an excellent advantage over Fletcher in the passing game. This will be critical for the Steelers’ success on third downs. Pittsburgh will likely employ double-tight formations on third downs if the distance is less than five yards, and they will look to exploit any Fletcher-on-Moore match-ups they see.

The key for Fletcher is going to be keeping Moore in front of him. The Steelers’ offensive line isn’t capable of sustaining blocks long enough to get Moore down the sidelines on a wheel route, so Fletcher should be able to defend in the passing lanes in front of him, and maybe grab an interception.