Sprint specialist Kittel, 31, split with his Katusha-Alpecin team to take a break from cycling earlier this year, following a rapid decline in form since 2017.
Tour de France: Why Mark Cavendish, Marcel Kittel and other sprinters had a premature end to 2018 race
How can established pros and multiple stage winners like Cavendish not be able to finish within the time limit? Here's why:
Tour de France: Sluggish Mark Cavendish eliminated after failing to make the time cut at end of Stage 11
Although given a warm applause for finishing the stage, sprint king Cavendish refused to speak to media at the finish line. He promptly turned around and rode downhill towards his team hotel.
Froome was attacked by Romain Bardet and Dan Martin in the lung-busting ascent to the Col du Galibier but he stayed calm and covered every offensive move.
Tour de France 2017: Chris Froome is vulnerable, but his challengers need to step up to dethrone him
With the toughest Alpine climbs coming in the last week, here's our analysis on what lays in store for the riders, particularly Chris Froome.
Tour de France 2017: Michael Matthews wins Stage 16 in a photo finish; Chris Froome retains yellow jersey
Australian Michael Matthews won his second stage of the 2017 Tour de France on Tuesday and closed in on the green jersey held by Marcel Kittel.
Marcel Kittel, the 29-year-old German, was at his imperious best in winning a fifth sprint finish out of six, once again making it look easy.
Tour de France 2017: Chris Froome retains yellow jersey, Marcel Kittel celebrates win after tenth stage
Relive all images from Day 11 of the 2017 Tour de France as Chris Froome and Marcel Kittel celebrate their wins after the tenth stage.
Marcel Kittel, the burly German, cantered to a fourth stage win of the Tour at the end of Tuesday's 178 kilometres 10th stage from Perigueux to Bergerac, as Chris Froome retained his overall lead.
The biggest winner from the first week is definitely Marcel Kittel. The German sprinter has won three of the nine stages in impressive fashion.
This was Kittel's second stage win of this Tour and 11th in total, moving him level with German compatriot Andre Greipel,
Cavendish was taken to hospital by ambulance with shoulder and finger injuries after crashing to the ground when Sagan shoved him into the metal safety barriers.
Take a look at Stage 3 of the Tour de France won by Peter Sagan
Germany's Marcel Kittel produced another show of raw power to win his second stage of this year's Tour de France on Monday, storming down The Mall for a commanding victory.
With huge crowds cheering him on, he tangled with Australia's Simon Gerrans and the two riders crashed spectacularly to the ground. Cavendish winced in pain and clutched his right shoulder.
Kittel, who won the first and 10th stages, stayed behind the Briton's wheel in the final straight and went past Cavendish at the very last moment.
Omega Pharma-Quick Step rider Cavendish appeared to leave his line and bumped into Dutchman Tom Veelers who lost his balance and hit the ground as he was leading out Kittel for the German's second Tour stage win this year.