Leeds United's pre-season schedule has provided a window into Marcelo Bielsa's thinking ahead of the new campaign.
The Whites and their U23s have competed in a number of friendlies, against a varied calibre of opponent.
Spanish sides Real Betis and Villarreal have given Leeds a test of their European credentials, while a 4-0 humbling at the hands of AFC Ajax was a reminder of just how competitive and ruthless top-level opposition can be.
The U23s have faced Guiseley, Jong Ajax, Manchester City U23 and Fleetwood Town, where the merits of regular senior football have been plain to see.
Marcelo Bielsa typically settles on a favoured XI early in the campaign, leaving very little to the imagination for opposition coaches.
Heading into this weekend's eagerly-awaited season opener at Old Trafford though, Leeds could be missing one of their key men for the first time, in a scenario which has not played out for five years.
Robin Koch has been Kalvin Phillips' stand-in throughout pre-season, as Marcelo Bielsa continues to trial the German international in his ultra-specific defensive midfield role.
Koch has largely been up to the task, with few - if any - glaring errors which raise questions over his suitability in that position.
Given Phillips' late start to pre-season, he has been eased back into action, first with a 45-minute run-out versus Jong Ajax in the Netherlands, before then seeing out the final 45 minutes of the senior squad's 2-2 draw with Villarreal.
For each of the last four seasons, Leeds' newest England international has started the opening game of the campaign, including each of the three campaigns under Bielsa.
While it is not a question of whether Koch threatens the status quo in midfield, there is a separate debate.
Will Phillips have demonstrated his preparedness in just 90 minutes of pre-season action?
Bielsa is known to protect his players when it comes to their fitness levels, not only demanding peak performance but equally not risking those who are not quite one hundred per-cent.
Phillips' increased involvement towards the end of pre-season indicates he remains Bielsa's preferred option at No. 6 - that fact is undisputed. Previous comments of Bielsa's do suggest he would have no reservations in deploying Koch there against Manchester United, if necessary.
Leeds' fitness coach Benoit Delaval and Bielsa will undoubtedly discuss the availability of key players this week, ahead of the team's visit to Old Trafford.
Last-minute hitches aside, Phillips will almost certainly be named in the matchday squad this weekend, but it may not come as too great a surprise if the England international starts on the substitute's bench as opposed to the starting XI.
