The club ended a rollercoaster season, which started with Frank Lampard signing seven new players last summer and ended with one of them scoring the winner against Man City for Tuchel.
Chelsea are interested in signing a new striker, with interest in Erling Haaland, Harry Kane and previously Sergio Aguero, who is expected to join Barcelona. Former player Romelu Lukaku is the latest name linked.
A midfielder is also of interest amid fresh links to West Ham's Declan Rice and could need another centre-back if one of their current crop leavel, with Bayern Munich pair Niklas Sule and Jerome Boateng reportedly of interest.
Tuchel has underlined the importance of keeping his squad fresh as they look to build on their Champions League triumph.
"Two or three could be very, very good," he told reporters. "It’s a constant thing to never deny change. "That you always bring new energy, new guys who question the old beliefs, who challenge everybody in the training and in matches, so I think it’s a good thing.
"We don’t need another seven and another complete turnover because it's also our job to keep on improving, because we have still a young squad and it's not about stealing from them the chance to prove it again that they are capable of growing and evolving.
"But we have some ideas, of course, to make the group stronger and I think this can always be a positive thing to challenge all of us."