The 26-year-old Sardinian was training on Sunday when he suffered an explosive puncture to his front wheel, causing him to lose control and hit the deck, with his kneecap taking the brunt of the trauma. Aru tried to ride his rollers in the ensuing days but begged off because of the pain.
"A part from some peeling, Fabio has suffered of a blunt trauma to his left knee with involvement of the patella. In the days following the incident, the athlete has been subjected to an investigation by MRI that confirmed the diagnosis above, excluding fractures," read a statement from the team.
Aru is still planning to start the Tour of the Alps April 17-22 as his last race before the Giro d'Italia starts on May 5.
Poels out of Ardennes Classics
Last season's Liege-Bastogne-Liege winner Wout Poels (Team Sky) will miss the opportunity to defend his title in the hilly French Monument and at the other Ardennes Classics as he continues to recover from a knee injury that sidelined him before the start of Paris-Nice, according to a report on Telesport.nl/.
Poels, who finished fourth at both the Volta a Valenciana and the Ruta del Sol earlier this year, scrapped plans to race in Paris-Nice after developing the knee injury. He has begun training again in full but is not yet ready to tackle Amstel Gold Race (April 16), Flèche Wallonne (April 19) and Liege-Bastogne-Liege (April 23).
Although it is not yet known when Poels will be able to return, Team Sky is hoping he'll be back in action by the Tour of Romandie April 25-30 before heading to an altitude training camp and then either the Tour de Suisse or Criterium du Dauphine to prepare for the Tour de France in July.
Boasson Hagen looking to build on 2016 Roubaix result
Boasson Hagen was one of five leaders who made it to the Roubaix velodrome in 2016 and battled for victory on the track's banks, where Mathew Hayman took the honours ahead of Tom Boonen, Ian Stannard and Sep Vanmarcke.
"I think it's going to be a hard and fast race on Sunday," Boasson Hagen said. "I'm really looking forward to it. I feel my condition has been getting better for every race I've done in this spring campaign. Last year was really good but I didn't win. Now, I'm ready to try again."
Boasson Hagen started his season in Portugal before heading to Italy for Strade-Bianche and Tirreno Adriatico, where he earned his best result of the season so far with seventh on the stage 7 individual time trial.
His results so far this spring in Belgium haven't turned any heads, however, with 22nd in last weekend's Tour of Flanders his best result there after placing 19th at Milan-San Remo.
Dimension Data for Paris-Roubaix: Edvald Boasson Hagen, Bernhard Eisel, Scott Thwaites, Tyler Farrar, Nic Dougall, Ryan Gibbons, Reinardt Janse van Rensburg and Jay Thomson