
That is particularly the case in defence, where Dionisi thought he might have Omar Traore and Branimir Mlacic fit for West Brom on Saturday, only to have them ruled out the day before the game and find himself chucking Albert Eames in for a first senior league start of his career.
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In midfield, every available player was selected from the start - other than Edo Kayembe, who played 45 minutes at left-back and was quite possibly benched just in case he had to deputise there.
Soumaila Coulibaly and Stephy Mavididi were available to play half an hour, Rocco Vata less (he didn't get on), while Myron Boadu was left at home completely.
Dionisi is having to get his abacus out just to work out the players he can have on the pitch at any one time, even plenty of his subs at The Hawthorns conditioned by availability rather than preference.
Soumaila Coulibaly on debut (Image: Alan Cozzi/Watford FC)
And the situation looks unlikely to resolve itself ahead of what is a big week of back-to-back home games.
While the Hornets' wretched long-term away form – eight wins in 53 league matches – shows little sign of picking up, they are going to have to pick up the majority of their points at Vicarage Road, not least against the likes of Preston North End and Stoke City.
The good news is that the performance level is still decent. Watford could easily have earned at least a point on Saturday, though Othmane Maamma's early miss was indicative of their regular struggles away from home.
Missing key chances and allowing the opposition to waltz through to take theirs is a running theme, and Maamma – whose early-season form is a concern – is one who still lacks a ruthless streak.
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But it was ultimately another afternoon of ifs, buts and maybes, which would well be cured by Dionisi having a full squad of players that is, literally, fit for purpose, particularly in defence.
"In this moment, it is this," he said afterwards, smiling his latest rueful smile. He now views the upcoming international break as the time when he may be able to get his squad into passable condition as an entire unit.
The constituent parts all seem to exist – except, perhaps, an extra midfielder – but are all at various stages of injured, knackered, or building fitness.
Hector Kyprianou and Maamma have been going hard for the last three months and have looked tired this week, while Edoardo Bove – fresher after sitting out of the first half against Swansea – appeared to have suffered a serious injury on full-time.
Edoardo Bove receives treatment at West Brom (Image: PA)
The initial prognosis is not so bad, though confirmation of the extent of the injury is still to come and any kind of meaningful absence would be a huge blow for a midfield unit Bove is increasingly holding together.
There's a chance Traore, Mlacic, Coulibaly and Jordan Zemura (also subbed with a small issue) will all be available for Preston, which is the first time Watford will be favourites to win a match all season.
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But there's also a chance they won't be, so expect the mix-and-match approach to selection to continue.
Albert Eames takes a throw (Image: Alan Cozzi/Watford FC)
Remarkably, Kayembe could start at left-back, while Eames will be in contention again despite obvious concerns about whether he meets the standard.
In isolation, the left-back situation is unlucky. Marc Bola and Zemura are a solid unit in that position, not particularly injury-prone, and Bola's hamstring pull has stuffed the Hornets.
While five points from the first three games could be said to justify delaying business, the knock-on effect has obviously been felt now the games are coming quicker and the initial first XI players are getting tired.
Iker Bravo crosses (Image: Alan Cozzi/Watford FC)
Scott Duxbury and Luke Dowling may have talked about having two good players per position this week, but what they omitted was the number of those players who are injury-prone or being run into the ground. How often will Watford genuinely have all of them fit?
For now, the coach they heap praise on is essentially having to make it up as he goes along, seemingly certain not to know who is available for Tuesday night until Monday lunchtime at the earliest.
In that sense, it is not just the number of absences but the lingering uncertainty as to who and what we're going to see that is causing Dionisi problems.
While losing at two decent sides away from home is excusable, that confusion resulting in a bad week in WD18 will set alarm bells ringing.