Brent Seabrook was in unfamiliar territory Tuesday morning and, as a result, was wearing a suit and tie Tuesday night. The Blackhawks veteran defenseman and alternate captain was one of the last players to leave the ice following the team’s morning skate after coach Joel Quenneville had told him he would be a healthy scratch. With the Blackhawks also in unfamiliar territory halfway through the season, in last place in the Central Division and tangled in a crowded playoff race, Quenneville and his coaching staff decided a shakeup was in order ahead of their 8-2 victory over the Senators on Tuesday night at the Canadian Tire Centre. Benching Seabrook was the most surprising of a flurry of moves the team has made in recent days as it struggles to qualify for the postseason for the 10th straight year. “Every game we measure performance and the contributions. A lot of guys, a lot of times aren’t deserving when they sit out,” Quenneville said. “We felt the other guys were deserving of playing tonight’s game. We think it’s a very limited experience for him. We expect him to get back in there.” Seabrook has been “in there” for all but 14 regular-season games since the start of 2006-07. He’s fifth in franchise history with 964 games played, plus another 123 in the playoffs. The 32-year-old also is in the second year of an eight-year, $55 million contract but hasn’t scored a goal since the season opener, more than three months and 40 games ago. He began the year paired with Duncan Keith on the Hawks’ top defensive line, but has played the majority of time lately on the second pairing with Connor Murphy.