Their packed fixture list starts with a Capital One Cup quarter-final at Sunderland on Tuesday, where the Blues boss is likely to rest some key players ahead of the Premier League showdown with Arsenal on December 23.
Mourinho is hoping to leave out John Terry for the trip to Wearside and recall Gary Cahill, who missed Saturday's 2-1 win over Crystal Palace with a thigh problem.
Branislav Ivanovic is suspended, so Cesar Azpilicueta will switch to his favoured right-back role, with Ashley Cole returning on the left.
"Now is an important period for all of the squad - everyone has a role to play and a contribution to give," Mourinho said. "Every player will be important when we have so many games and competitions to play."
On his plans for Sunderland, he added: "Azpilicueta can go on the right, Ashley Cole on the left, with David Luiz as a central defender.
"If Cahill recovers, I will play him, if he does not recover, then I will go again with John, but I would like to John a rest for that match."
Mourinho has been impressed with the efforts of the Blues skipper, who has made 23 appearances since returning to the first-team this season.
"John is very solid, very focused with the ball he makes the right choice, and without the ball he is also very focused," said Mourinho.
"I think he is having a very good season, let's see if he can keep going this way because he has been fantastic."
Chelsea closed the gap on Arsenal at the top of the Premier League over the weekend, and Terry has called on his side to maintain their momentum heading into the new year.
"We go to Sunderland again on Tuesday night in the Capital One Cup and then we have a really busy spell of league games over Christmas, starting with Arsenal away on Monday week," the Blues captain said.
"With the games coming so regularly, it is up to us to build some momentum and push on in the league and the cups."
Chelsea could leapfrog Arsenal with victory at the Emirates Stadium next week, but Mourinho insists league positions count for little in January.
"I like the fact we will go there with this distance (between the teams), because it brings even more ingredients to the game," he told Chelsea TV.
"However, I don't think in this league it will become a crucial game, if we leave Arsenal with five points difference or top of the league.
"I don't think it will make a big difference in terms of what is going to happen in the future because the league (this season) is like this."
Watch Sunderland v Chelsea live on Sky Sports 1 HD from 19.30 on Tuesday