You are right, seeing Chelsea's potential in the Premier League is very difficult. Especially with the capital points they have and the remaining matches it will be increasingly difficult to get past the club above them. Chelsea's Premier League play has been terrible and this season Potter hasn't produced great results against Premier League clubs.
Sterling and Harvertz saved the ass of Potter and he will have chance to continue his job in Chelsea.
In Premier League, it is very unrealistic to think Chelsea will be able to end at the fourth position, not higher positions in top four.
They do look to be chasing the Champions League, but even then they are still in the last 16 while the opponents they will face will be much stronger.
A best possibility for Chelsea is to focus on Champions League and win it. At least they already get a spot for quarter final round and to win Champions League, they will have to play 5 matches including the final match. It is not easy but in Champions League and at knock-out rounds, everything can happen and strongest teams are not champions in all seasons.
Chelsea is already at the bottom and it needs to take the small team seriously to make sure if Chelsea will able to win and get full points by the end of the season. UCL is the only trophy that can be won by chelsea. I see no chance for chelsea to be qualified for UCL if chelsea keeps losing more and more points in EPL. The good result against leeds didn't prove that chelsea backs on its best performance. Chelsea needs to win a few more matches in a row.
They don't stand at bottom of table but their position is not good. They have big gap with top four and with good forms of clubs in top six and above plus a very poor form of Chelsea, it is impossible for Chelsea to beat all above clubs and enter top four.