Something is seriously wrong with Giorgio Chiellini.
Juventus fans have sensed it for the entire season. Normally an irresistible combination of technique and savage physicality, Chiellini has looked decidedly human since the season opened in August.
A quick look at the statistics confirm the eye test. According to WhoScored.com, Chiellini is recording nearly a tackle per game less than a season ago, and his pass-completion percentage has dropped. Normally imperious in the air, he's winning fewer aerial duels this season in both Serie A and the Champions League.
Chiellini has always been one of Juventus' most consistent performers. Underrated outside of Italy, he's probably one of the top five center-backs in the world, and is so respected in Turin that he's practically a shoo-in for the captaincy whenever Gianluigi Buffon decides to call time on his career.
So what is it that's wrong?
In the opinion of this writer, there are two issues, one minor and one very major.
The first, more minor explanation is Massimiliano Allegri's mid-season formation change. The switch from the 3-5-2 he had run in for the last three years under Antonio Conte to the 4-3-1-2 that the Bianconeri currently run has certainly taken some adjusting.
In the 3-5-2, Chiellini had broad license to press forward from his spot on the left side of the back three. Using the skills left over from when he started his career as a left-back, Chiellini was an extra body in the attacking half and added to the width of left side of the field.
That role is now more the full-back's, but Chiellini can still be spotted roaming high up the field on occasion when he should be hanging back to defend. It's clear that he's not used to his new positioning, and that's caused all kinds of havoc.
In open play he's been out of position, opening gaps for counterattacks or, as was the case in the Supercoppa, leaving tons of space between himself and the man he should be marking.
Time will likely fix this problem as Chiellini gets used to his new place on the field. Unfortunately, extended time on the field might exacerbate the second problem.
A simple look at the tape is enough to see that exhaustion is starting to take hold of Chiellini. His reactions are slower, his passing is sloppy and his decision-making is leaving a lot to be desired.
Since Conte's arrival in 2011, Juventus has advanced deep into European competition twice—the quarterfinal of the 2012-13 Champions League and the semis in the 2013-14 Europa League.
Between last summer's World Cup, Euro 2012 and the 2013 Confederations Cup, Chiellini has also played in major international tournaments in each of the last three summers—two of which took place in the grueling heat of Brazil.
In a word, he's played high-level soccer for three years straight with hardly any break. Injuries to Andrea Barzagli and Martin Caceres have kept Allegri from properly rotating the back line and giving his starters rest, further exacerbating the problem.
If Barzagli were to return from his nagging heel and ankle injuries looking as he's looked the last three seasons, it may behoove Allegri to give Chiellini an extended run on the sidelines to allow his body to recover for the stretch run of the season.
Chiellini is still one of the best defenders in the game. His struggles are rooted in the natural adjustment period that accompanies midseason tactical changes and, most importantly, a level of fatigue that he probably can't stand much longer.
Time on the field is both the answer and the enemy here. The more time Chiellini has in his new responsibilities in a back four, the less positioning will be a problem. But right now, the more time he spends on the field, the more he's taxing a body that's likely already pushing its limit.
How Allegri manages these dueling concerns will go a long way toward determining whether or not Juve's defense remains leaky in big games—and whether or not the Bianconeri will claim their fourth consecutive Scudetto.