The 38-year-old Norwegian announced last October that he would transition from rider to directeur sportif with the squad after the Spring Classics, but admitted to TeamSky.com that he expects Sunday to be an emotional day, but the prospect of a new role brings excitement.
"Of course, it will be emotional after the race on Sunday, and I think if I'd quit cycling straight after retiring, it would have left a big hole in my life, but now I have new goals to motivate and challenge me," he said.
Rasch hasn't hung up his wheels just yet, and is hoping for that magical perfect race to achieve his best ever result in his sixth attempt at Paris-Roubaix.
"I know if everything goes my way, and I am really lucky, that I can be up there at Paris-Roubaix," he said. ""First and foremost, I'll be looking to help our team leaders, but I'd still like to be competitive myself and hang in there for as long as possible. If you've got the form on the day, you'll always have a chance because it's such an unpredictable race.
"I think my strengths as a rider suit this type of race but everything still has to run perfectly. The Classics are the hardest and best races in the sport in my opinion – and Paris-Roubaix is the biggest of them all. It has so much history and so many people turn out to watch it. I love everything about it and I'm pleased I've got the chance to ride it one last time."
Although Rasch won the Norwegian road race title in 2003, he was a relative latecomer to the upper echelons of the sport, making the step up to ProTour level at the age of 32 with the Crédit Agricole team of fellow countryman Thor Hushovd in 2008.
Rasch joined Hushovd at Cervélo TestTeam and Garmin-Cervélo in the years that followed, before parting company to sign for FDJ in 2012. At the end of last season, he was linked with a move to IAM Cycling, but ultimately opted to sign for Team Sky.
Rasch was part of Sky's classics squad in 2013, where he rode alongside Edvald Boasson Hagen and Geraint Thomas, and has continued in the role this season.
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Following Sunday's race, Rasch will have some time to celebrate his career before starting his new position as DS at the Tour de Romandie. He said that physically he could continue to race, but opted to take the opportunity to move into this role at Sky while it was available.
"You never know when a chance like that is going to come again, especially not with a team like Team Sky," he said. "My head definitely made the decision for me, not my legs – they still feel strong. I turned professional quite late in my career so I'm not tired of the bike, training or racing.
"Although it's a logical step, being a DS is a completely different job to being a rider so I will need a few races as a second DS to learn the ropes before I start leading teams on my own."
He will lead the Tour de Romandie team with Servais Knaven, another Classics man turned DS.
"I'm fortunate because there's a great group of guys here to learn from. All the DS's are young, ex-riders, and they will all help me a lot. Having that set-up in place at Team Sky was really important for me. The staff we have here are all really positive and they want to help me learn."