Image 1 of 5 Marcel Kittel (Katusha-Alpecin) (Image credit: Justin Setterfield/Getty Images) Image 2 of 5 Marcel Kittel in the Scheldeprijs peloton (Image credit: Getty Images) Image 3 of 5 Marcel Kittel (Katusha-Alpecin) (Image credit: LaPresse - Ferrari / Paolone) Image 4 of 5 Marcel Kittel (Katusha-Alpecin) wins the Trofeo Palma (Image credit: Getty Images) Image 5 of 5 Marcel Kittel poses for a selfie (Image credit: Getty Images)

Marcel Kittel's return to racing has struck a further delay, with the German sprinter now pulling out of the Amgen Tour of California.

Kittel hasn’t raced since finishing 99th at Scheldeprijs on April 10, and his California absence follows a late withdrawal from last week’s Tour de Yorkshire.

Katusha-Alpecin confirmed the news to Cyclingnews on Wednesday, giving the same explanation as for Yorkshire, that Kittel is not healthy enough and not ready to race.

The withdrawal is the latest setback in a difficult period for the 30-year-old, and leaves him with a mountain to climb if he is to get back on track for the Tour de France, which starts in just under two months.

After a disappointing first season with Katusha in 2018, Kittel underwent blood tests to get to the bottom of his problems, and it seemed like he had put things right when he won the Trofeo Palma at Challenge Mallorfca in his second outing of 2019.

However, after finishing third in a stage of the UAE Tour, he struggled in the crosswinds at Paris-Nice and abandoned on stage 4. He then went to Belgium for the Classics but did not figure in the bunch sprints at Driedaagse Brugge-De Panne or Scheldeprijs. The latter was particularly concerning as he finished 99th and 4:30 down at a race he had won five times in the past.

In the wake of that race, debate started to rage over Kittel's lack of form. Katusha-Alpecin director Dirk Demol said it made "no sense" that he was dropped on the flat, while former pro Jurgen Van Den Broeck, commentating for Sporza, voiced rumours that Kittel was "not busy with his profession" and was "drinking too much beer and wine." Kittel’s agent vehemently denied those rumours.

In his own statement on social media, Kittel said: "Always easy to beat a man when he's on the ground. I'm facing a difficult period and I'm thankful for everyone who is supporting me now. To those people making headlines on my cost now: enjoy your minute of fame!”

Kittel was due to return to action at the Tour de Yorkshire last week, but, after being announced as one of the star riders, he decided not to travel to the UK. His team said it was down to “health issues” but insisted Kittel was still set to race the Tour of California, which runs from May 12-18, as planned. However, this week they took the decision not to travel to the US.

It is unclear when Kittel will next race. Last year he followed California with the Rund um Koln, Tour of Slovenia, and German nationals ahead of the Tour de France.