Since the opening day of the Premier League season we have seen familiar players excel and under-perform, new signings flatter to deceive and extravagant amounts of money spent on fresh arrivals.

That has resulted in managers up and down the country being left with some important calls to make this weekend, decisions that could potentially signal a player's squad status for the rest of the campaign.

Below, Sports Mole takes a look at five players who may or may not find themselves in the starting lineup.

1. John Terry

Before last Sunday, Chelsea defender John Terry hadn't been substituted by Jose Mourinho in 177 matches, so when the Blues skipper was hauled off after 45 minutes against Manchester City, most people were understandably surprised. The 34-year-old had been part of a Chelsea backline that had been ripped apart by a relentless offensive performance from the likes of Sergio Aguero, David Silva and Raheem Sterling, but he shared equal blame with his teammates.

The decision to replace Terry with the faster, younger Kurt Zouma was a big call by Mourinho and it has arguably left him in a position where he is signalling how he sees the club stalwart by his selection against West Bromwich Albion this weekend. It is no secret that the Portuguese is looking for a fourth centre-back - Everton's John Stones is his number-one choice - and from the outside looking in, it appears as though he is already planning for the future.

However, as far as the match at The Hawthorns is concerned, can Mourinho really afford to leave Terry on the bench? He is blessed with three of the best central defenders in the world, but Terry has long been the leader at Stamford Bridge and after a poor start, it can't be seen that Terry has been demoted from first name on the team sheet to part of a rotation policy. It would be considered an over-reaction and would do little to quieten speculation linking the former England skipper with a lucrative move abroad.

2. Branislav Ivanovic

Terry's Chelsea teammate Branislav Ivanovic is another member of the defence who is reportedly not guaranteed his place in the team against the Baggies. The versatile Serbian is arguably the club's best ever right-back, but he has been criticised for his performances over the first two games after having his lack of pace exposed by Jefferson Montero and Sterling.

His average performances have come at the wrong time with Chelsea bringing in Baba Rahman from Augsburg, which was announced just a few minutes after the Man City debacle. If reports are to be believed, Rahman has been lined up for an immediate debut with Cesar Azpilicueta switching flanks to take Ivanovic's spot at right-back.

Given that he was handed the vice-captaincy duties at the start of the campaign, it would be seen as a bold move by Mourinho, but it is perhaps one that he feels is necessary. Chelsea have struggled for competition in the full-back areas, especially with Azpilicueta filling in at left-back for most of last season, and Mourinho may feel that dropping the 31-year-old will improve his game.

3. Nicolas Otamendi

When you spend over £30m on a central defender, while also handing him a five-year contract, sooner rather than later he is going to be in the side. Manchester City manager Manuel Pellegrini will be aware that he is effectively obligated to find a place in his starting lineup for Nicolas Otamendi, but the question is, when will he introduce him?

Throughout the summer, City were linked with a vast array of central defenders after their struggles in that area last season, but Eliaquim Mangala, regarded as a big-money flop last season, has returned with a point to prove, and so far, he has been excellent. Based on his performances against West Brom and Chelsea, he has struck up a good rapport with Vincent Kompany and it would be a dangerous move to break up a winning partnership.

However, it appears a case of when, not if, Otamendi will make his full debut. He may have to settle for a place on the bench against Everton at Goodison Park, but if Mangala delivers another assured display, he will quickly find himself under the spotlight when he does feature for the Citizens.

4. Younes Kaboul

After Dick Advocaat guided Sunderland to safety at the end of the last campaign, he was left with the task of strengthening the Black Cats squad. On paper, he has done some good business, but it has quickly become apparent that it hasn't been enough to solve their problems in defence, with seven goals being conceded against Leicester City and Norwich City.

Five million pounds were spent in forming the partnership of Sebastian Coates, who impressed on loan last season, and Younes Kaboul, but they have looked far from commanding and at least one of them looks a certainty to be out of the team against Swansea City on Saturday. Advocaat may have more faith in Coates given his performances in the spring, which leaves Kaboul in line to be dropped.

Before his move to the Stadium of Light, the Frenchman's last competitive game had come on January 24, and his lack of match action has showed. With a crisis meeting having already been called, Sunderland can't afford a third straight defeat, and with John O'Shea waiting in the wings, the change could be made.

5. Gokhan Inler

At the start of April, Leicester City appeared certainties for an instant return to the Football League, but in the space of six months, they have been transformed into a team who have collected 28 points from their last 11 top-flight fixtures and who are attracting experienced internationals from all around Europe.

The signing of Gokhan Inler from Napoli is one of the coups of the summer. Over the past eight seasons, he has made 328 appearances for Udinese and Napoli and he represents the perfect replacement for Esteban Cambiasso. However, despite everything he will add to the Foxes, he is not a certain starter this weekend.

Claudio Ranieri will be keen to draft the Switzerland captain into his team as soon as possible, but the veteran boss won't want to do anything to upset the apple cart at the King Power Stadium. Expect Inler to feature at some stage, though, with his know-how potentially proving key in the latter stages of their fixture with Tottenham Hotspur.