Thomas Tuchel has not ruled out signing another striker but refused to be drawn on whether Chelsea could move for Cristiano Ronaldo orRobert Lewandowski.The Blues on Wednesday made their first big signing of theTodd Boehly era, landing Raheem Sterling from Manchester City for a fee reported to be in the region of45million.Ronaldo has been linked with a move Blank Jersey to Stamford Bridge after he did not travel to Thailand and Australia for Manchester Uniteds pre-season tour.Lewandowski has informed Bayern Munich he wants a new challenge, although Barcelona are the favourites to sign the prolific striker.Tuchel says the London club may bring in further David Robertson Jersey firepower, but gave little away when asked about Ronaldo and Lewandowski.He told Sky Sports: I will not comment on them, their careers speak for themselves and its not needed that I give another comment and put rumours out there, which do not help anybody. We will announce when something is to be announced.Asked about the prospect of signing another striker, he said: I would not rule it out, but its not the priority. I think the priority right now is JT Realmuto Jersey defence, which everybody knows, its not a secret. We need to see what is po sible. Napolis Kalidou Koulibaly is expected to bolster Chelseas defence, while Nathan Ake appears set to return to the club from City after sanctions were lifted on Darren Daulton Jersey the club following a change of ownership.Tuchel says it is vital more new faces arrive, withAntonio Rudiger,Andreas Christensen and Romelu Lukaku having departed.The German said: The stakes are high and were competing not only against the best teams who have ever played in the Premier League but also the best coaches,We come from sanctions, we come from losing top-quality players, key players, we are a club in transition, in transition of ownership, we were behind in the transfer race and we were behind in the table. So we have things to improve. Will Middlebrooks Jersey The signing of Raheem shows what were capable of doing, it shows the ambition of the club and the ownership and its good because were all here to win and compete.We love to compete and we love the challenge at the very top. For that we need signings of new quality players or otherwise theres no chance.