Ronald Koeman faces challenge in trying to juggle Everton's rotations

At a time when the majority of teams barely are through their first game of the new season, manager Ronald Koeman is preparing his Everton side for their fourth competitive outing in 2017-18.

Thursday night brings Hajduk Split to Goodison Park in the first leg of the Europa League playoff round. This is the second of five competitive matches in a 16-day spell that started with last weekend's victory against Stoke.

With the first leg of the previous Europa League qualifying round taking place in July, this is the earliest start to a season in Everton's history. Progress across the cup competitions could see it become one of the longest, which would be in sharp contrast to Koeman's first season. Early exits in both domestic cups handed Everton just 41 matches in all competitions last season. Europa League games alone will take the Toffees beyond that total this term.

Additional fixtures bring new challenges and finding the right approach is pivotal, especially when adjusting between Europa League and Premier League within the space of a few days. In this regard, the toughest test could be the earliest. On the back of the home leg on Thursday, next week sees the second leg in Croatia sandwiched between Premier League trips to Manchester City and Chelsea in the space of six days.

Astute use of the older players in the squad is vitally important, as the longer season inevitably will require sensible rotation. Wayne Rooney, scorer of the winning goal on the opening day, is among those that Koeman has to carefully manage. Rooney, who turns 32 in October, has played all but four minutes of the three matches thus far. The upside for Koeman is the versatility of other squad members who are able to cover his position, especially if his primary use is in an attacking midfield role.

It is in defence where the most delicate challenge exists, with three of the more prominent squad members short on sufficient cover. Leighton Baines is 33 come December, while central defensive pairing Ashley Williams and Phil Jagielka turn 33 and 35, respectively, within the next few days.

Baines has long been ever-present in the side due to his ability, but his importance is heightened by the lack of alternative options in the left-back position. He has played every minute in the three opening games.

Similarly, while Michael Keane appears the undoubted first choice at centre-back, the changing systems, switching between three- and four-man defences, and lack of alternatives mean fewer opportunities to rest or rotate Williams and Jagielka.

As was evident against Stoke on Saturday, Koeman's occasional use of three centre-backs in the same starting XI leaves few options in reserve. Mason Holgate lacks first-team experience as a centre-back in a four-man system, while Muhamed Besic operated in central defence in preseason but doubts over his temperament count against his claims in a competitive outing. A four-man defence with Keane as the mainstay, and Williams and Jagielka alternating alongside him, appears the most suitable solution unless new defensive arrivals are forthcoming.

If nothing else, these concerns and the possible season-long absence of Ramiro Funes Mori through injury explain why Koeman is keen to recruit a left-sided centre-back before the transfer windows closes, ideally one that also can cover the undermanned left-back position and lessen the burden on Baines.

While Koeman has to be pleased with how the defence has begun the season, there are much tougher tests ahead. Despite the use of different personnel and defensive systems in each of the three games to this point, there have been three successive clean sheets amid a trio of 1-0 wins to open the season. Even with uncertainty over the starting XI and formation, the general defensive improvements evident during Koeman's debut campaign continue to develop.

Yet the uncertainty over the starting XI is an issue that needs considerable attention. While extra matches increase the likelihood and need for rotation over the course of a season, a so-called "best team" is necessary for any manager, a default setup for more difficult matches.

Perhaps unsurprisingly after a busy summer of transfer activity, as shown through the use of a different formation in each half during the Stoke win, Koeman still is figuring out his best system and the players most suited to it. In terms of utilising the squad, a solution to this problem is every bit as important as the rotation of players amid fixture congestion. Europa League involvement makes an already daunting opening run of games that much harder, but this frantic sequence marks progress. Regular European football is one of the first steps toward moving the club forward under this new regime.

Thursday's tie against the team finishing third in the Croatian top flight last season is the first significant test of Everton's strength in depth. Koeman faces a careful balancing act while also working to fine-tune his team.