Already-injured champ Froome faces cobble trouble today

LILLE, France (AP) - Back on the race's home turf after three days in England, the Tour de France pack faces a first possible shakeout today over nine patches of bone-rattling cobblestones in northern France.

Many riders were expressing dread of the forecast for rain, meaning the cobbles will be slick.

For defending champion Chris Froome, a crash that scuffed up his left knee and elbow and injured his wrist Tuesday in a nervous, crosswind-swept Stage 4 couldn't have come at a worse time.

Astana team leader Vincenzo Nibali of Italy, who kept the yellow jersey, decried a "crazy race" in Tuesday's 101-mile ride along the Belgian border. Froome and two-time champ Alberto Contador are among 20 riders trailing Nibali by two seconds.

Here are some storylines from Tuesday's stage:

KITTEL MAKES IT THREE: Marcel Kittel got his third stage victory in this Tour and the seventh of his Tour career Tuesday. Unlike his wins in Stages 1 and 3, when he made victory look easy, Kittel eked out victory by a half-wheel length at the end of the ride from Le Touquet-Paris Plage to Lille Metropole.

Kittel, of the Giant-Shimano team, didn't celebrate this time, but panted. The gesture at the line came from runner-up Alexander Kristoff of Norway, who swatted the air in frustration after being beaten by the barreling German. French rider Arnaud Demare was third.

After a difficult day of crosswinds, pockets of rain-smattered roads, and jumpy nerves in the peloton, Kittel said: "It's never easy ... (I was) lucky just enough at the finish line."

THE CHAMP CRASHES: Minutes into the stage, Team Sky leader Froome went tumbling after one rider bumped another - like a succession of dominoes - who crossed the Briton's front wheel. He skinned up his left knee, left elbow and hurt his left wrist, but got back on his bike. Clinging to the race doctor's car, he got bandaged up and rejoined the peloton. Then a teammate dropped back to get a splint at Sky's car, and pedaled it up to the ailing Froome.

Race doctor Florence Pommerie told French TV his injuries amounted to "essentially a few scratches."

Nibali, said his team informed him through his earpiece about Froome's mishap, and went back to see whether he was OK. Froome responded, "more or less," according to the Italian. The Sky leader went straight into the team bus and didn't speak to reporters after the stage.

Dave Brailsford, the Sky team boss, said Froome described feeling good at the end. Froome was undergoing X-rays after the stage, but the team didn't immediately comment on the results.

LOSE ENERGY AGAIN?: In the sixth stage of the Criterium du Dauphine race last month, Froome took a spill during a descent and banged up a hip, shoulder and elbow. The next day, he lost the race's yellow jersey to Contador - citing stiffness in his thighs and a loss of energy from the crash.

An aching wrist could mean pain ahead for Froome. The cobbles on today's 97 miles from Ypres, Belgium, to Arenberg Port du Hainaut, could make it difficult for him to keep his hands on the handlebars. It includes stretches of bumpy road familiar to riders of the famed Paris-Roubaix one-day classic.

"It's going to be a crazy stage for everyone (today)," said Philippe Mauduit, a sports director for Contador's Tinkoff-Saxo Bank team. "We'll do whatever we can to stay near the front to avoid getting involved in crashes or held up by any pile-ups, but that's what everybody wants and therefore the pace will be extremely high."

Said Nibali: "(Today), we just have to make it through the day ... Let's hope it's not raining."