Silva, Fernandinho add to Guardiola's injury woes
Silva will be out for "a few weeks" after sustaining an apparent hamstring injury in City's 2-0 Premier League loss at Chelsea on Saturday.
Fernandinho completed his team's first league defeat of their title defence but appeared in discomfort towards the end of the 90 minutes.
Kevin De Bruyne's ongoing rehabilitation from a knee ligament injury means Guardiola's first-choice midfield three from last season are not available to take on Hoffenheim, with a point required for City to secure top spot in Group F.
Sergio Aguero remains out with an abductor complaint, although the Argentina striker could be back when City host Everton on Saturday, while full-backs Benjamin Mendy and Danilo remain on the sidelines.
On Silva's injury, Guardiola explained: "He was substituted for a muscular problem. He will be stopped for a few days, a few weeks
"Maybe Sergio has a chance for the weekend.
"We have 15 players available, so rotating, I cannot do it too much.
"We are in a real tough game. We are in the next stage, that is important. We want to win the game because every game we have to try to win, [we want] to finish first.
"It doesn't matter if you finish first or second, the last 16 is always tough."
Desapontado com o resultado mas não podemos baixar a cabeça. Temos muito pontos ainda a disputar e voltaremos mais fortes.
.
Disappointed with the result but we wont lower our head now. We have a lot of points still to play and we will come back stronger.#wearecity #together pic.twitter.com/CXKQl86wMV
— Fernandinho (@fernandinho) December 9, 2018
Guardiola spoke of how highly he rates Hoffenheim counterpart Julian Nagelsmann, dating back to their meetings when the Catalan was in charge of Bayern Munich.
Hoffenheim's efforts in their 3-2 defeat to Shakhtar Donetsk last time out in the Champions League, despite being down to 10 men, gave Guardiola a newfound admiration for their play.
"Hoffenheim against Shakhtar was one of the most incredible games I watched as a spectator in the last years," Guardiola added, having studied a recording of the match this week.
"They were incredible how they created, how they did it – even with 10 players for 30 minutes, and they lost!
"It was fascinating watching that game. My admiration and point of view of Hoffenheim has increased. I know about Julian Nagelsmann and his team and I realise how tough it will be."