The Germany international had a mixed first season with the Blues, scoring just six Premier League goals in 35 outings, but he did net 12 times and provided 15 assists across all competitions.
However, according to The Sun, Tuchel wants to keep the 25-year-old at Stamford Bridge, as he views him as an important player for the capital club moving forward.
Werner played as a left-sided attacker on a number of occasions last season but was more often than not used through the middle by his Premier League club.
Chelsea are thought to be determined to sign a new striker in the current market, and Real Sociedad's Alexander Isak has allegedly been identified as an alternative to Borussia Dortmund's Erling Braut Haaland. body check tags ::