Chelsea captain John Terry has insisted he has not been assured of a starting spot by Jose Mourinho this season.
The former England defender often found himself overlooked by Rafael Benitez in the latter part of the previous campaign as he struggled to maintain his fitness.
Terry has played the full 90 minutes in each of Chelsea's opening Premier League games this season, but remains aware he will have to impress to cement his place in the XI.
"[There are] no guarantees you will be in the side, nothing," Terry told Sky Sports Radio.
"Whether you are captain or not, he made that very clear from day one."
Chelsea face Manchester United on Monday night in an early meeting between two clubs expected to be challenging for the title come the end of the season.
However, Terry does not expect the result to have too much of a bearing on the final standings.
"I don't think it is going to make or break the season," he added. "It could be one of them - a head-start for either side.
"But we have a good record going to Old Trafford over the last few years and that will serve us well.
"Obviously it is David Moyes' first game at the stadium so we are expecting quite a hostile atmosphere anyway.
"But we will go there and look to stay solid for the first 10 or 15 minutes anyway. We know it is going to be a tough place to go and they have had a good win against Swansea.
"But the two wins for us will serve us well and we go there full of confidence."