It will be Costa’s first Chelsea appearance since the October 5 defeat of Arsenal. He has missed the past four games after picking up a hamstring injury during an international window in which he played almost every minute of the games against Slovakia and Luxembourg.
The striker had made an excellent start to his Stamford Bridge career, scoring nine goals in seven Premier League appearances, but has been unavailable for the matches against Crystal Palace, Maribor, Manchester United and Shrewsbury through injury.
“It is good for us,” said Mourinho. “It's difficult when you only have one striker available, but when you have two the situation improves.”
Mourinho admits he is powerless to stop Costa from joining up with the Spain squad for their European Qualifier with Belarus on November 15 and Germany, their successors as world champions, in a friendly three days later.
Asked whether Costa would be part of the Spain contingent, Mourinho said: "That's not my call, that's not my decision.
"I'm nobody to stand in the way. I cannot stop him from going."
Mourinho, perhaps in a statement directed towards Spain boss Vicente del Bosque, is adamant the £32million signing from Atletico Madrid will be handled with care.
Mourinho added: "Again he needs to be under special care and we are going to do that. It's the only thing we can do.
"I'm always supportive of players playing for their countries when the players are in condition to do it and when the players in the national team follow the same kind of procedures to recover from the problems they have."
Costa's absence has been made worse for Mourinho as striker Loic Remy suffered a groin injury in the defeat of Maribor, who Chelsea play in Champions League Group G next Wednesday.
Costa's participation in Slovenia is by no means certain.
"Let's see step by step," Mourinho said. "With his situation it's difficult to predict what can happen."
The saving grace has been the form of 36-year-old Didier Drogba, who has scored in three successive matches against Maribor, Manchester United and Shrewsbury.
Those goals were Drogba's first since his return to Stamford Bridge following a two-year absence after eight years and 157 goals.
"For such a legend in this club, it's a difficult decision to take," Mourinho added.
"We took it together: owner, board, me, him, all of us together.
"To be important you don't need at the age of 36 to play 90 minutes of 50 matches.
"To be important you need to be there when the team needs you to be there.
"He was fantastic for us in the last week when we were in real trouble, without Diego and without Remy.
"And doing something that nobody should do, which is to play two 90 minutes of football with 48 hours difference. He managed to do that in an absolutely fantastic way."