I think he can, Ronaldo hasn't played for another champion league side at the start of the season so that won't be a problem. I have seen clubs make use of their January signing to play games in the champions league and that's what signing Ronaldo's will be like. If Ronaldo's knew he can't play then he won't be looking for a champion league team. Reporters of Chelsea striker Broja having possibility to miss the whole season is circulating and this means Chelsea needs a striker to back Aubameyang up.
Having to circulate between Ronaldo and Aubameyang would be awesome as both are experience strikers that can get us goals when we need them. Chelsea needs to be serious in his round of 16 stages, we shouldn't start this the same way we started the season or we'll be knockout very early. Dortmund attack are scoring lots of goals in their game meaning our defense needs to be fully fits to be able to stop Dortmund.
Ronaldo could improve the attack of any team, but I have not yet seen news that he can become a Chelsea player. At the moment he is training at the Real Madrid base, but it looks like, he just training there until he finds a new club. Today I saw the news that Newcastle is interested him, but it's all rumors, so far nothing is clear. Now again the football world will be watching Ronaldo and his search for a new club.
After being sacked by manchester and also portugal eliminated from the world cup, automatically ronaldo is now a free transfer player and it is possible for him to play anywhere later when it league starts, so far arab clubs have indeed been rumored to want to sign ronaldo but ronaldo desire to play in the champions league is ronaldo reason refused the club offer, I think so far Madrid has been Ronaldo home so when he is unemployed like now it is certainly not surprising that he is training at Madrid but even so it seems unlikely that Ronaldo will return to wearing a Madrid jersey, because previously Madrid had stated if there is no interest for madrid to re-sign ronaldo at this time, so inevitably ronaldo must be able to immediately find another club to continue his career, in my opinion, Newcastle which has now turned into a rich and strong club should be a consideration for ronaldo if their want to sign him, even though this season newcastle is not playing in the champions league but newcastle chances are wide open enough to end the season in the champions league zone this season.