Are Isaias' struggles down to the player, or Adelaide's system?
Adelaide United midfielder Isaias' sub-par performance and red card in last night's Original Rivalry capped off a disappointing few weeks for the Spaniard.
The Spaniard struggled in United's clash against Melbourne Victory, but this performance was not a one-off for Isaias; the 34-year-old has been ineffective for most of the season now.
Mixed performances against Brisbane, Melbourne City, Perth, and now the Victory upset Adelaide fans, who have been clear on how they feel about his latest displays for the club.
He currently leads the league for most red and yellow cards received this campaign, which are two stats you do not want your defensive midfielder to hold.
In attack, in particular, his passing this season has been nothing short of woeful.
Isaias is 33rd in the league for accurate passes per game.
He is also a lowly 53rd for key passes per game, averaging 0.8.
Isaias in action during Adelaide's 4-0 thrashing of the Wellington Phoenix recently. (Adelaide United)
The majority of Adelaide's squad find themselves outside of the league leaders for most of the stats above.
Meanwhile, some of their players are among the leaders for most cards collected, with Isaias and Javi Lopez tied for most red cards now.
Jacob Tratt also has four yellow cards.
The run of poor form for Isaias indicates that Carl Veart may not be employing the right tactics within the Adelaide midfield to get the best out of the veteran.
Or, perhaps he has genuinely suffered a drop off in quality.
This player is not the Isaias we saw that first joined the South Australian club in 2013.
Perhaps Veart has not been utilising a system that compliments the midfielder properly.
Adelaide could change the system by bringing in a more defensive-minded midfielder, allowing the Spaniard to move further up the pitch.
During his tenure as head coach, Veart has often operated with a midfield three consisting of a single number six, with two more advanced number tens.
But the draws against Melbourne City and Brisbane highlighted an issue with Isaias as a single pivot in this system.
Isaias never really influenced either game.
Both opponents deployed a strike partnership that effectively cut the passing lanes into the Spaniard in the build-up phase.
Both an individual dip in output, and tactical tweaks, have played a part in Isaias' struggles. (Adelaide United)
When the same issues started occurring in the first half of the first Original Rivalry of the season in Adelaide, Veart briefly made a change.
Louis D'Arrigo was instead asked to occupy the number six role, whilst Isaias pushed further forward as one of the tens with Stefan Mauk.
Adelaide still struggled, though, so Veart looked at whether his lineup required a personnel change.
Juande has since come in for D'Arrigo.
The Reds now utilise a double pivot in midfield more often, with two number sixes, whilst Mauk has played as a lone number ten instead.
The pivot worked wonders against the Wellington Phoenix on New Year's Day.
Isaias and Juande's ability to become false fullbacks in possession allowed Ryan Kitto and Javi Lopez to advance higher up the pitch.
But it still hasn't truly unleashed the Isaias of old.
That's because there are overarching issues with the team playing a part in the Spaniard's form, as highlighted in the 1-1 draw last night.
In the first half at least, Mauk made clever movements to pin Rai Marchán back and prevent him from applying pressure on Isaias.
But the Reds back four failed to find the unmarked Spaniard quickly enough when he would have been able to turn on the ball and play forward with the time on the ball a midfielder like him needs.
Granted, Isaias was also a culprit of some bizarre overplaying in dangerous areas that nearly gifted Victory clear-cut opportunities, particularly in the first half.
However, in recent weeks, the structural issues surrounding Isaias could well be why he has been performing so poorly in his midfield role.
He also isn't showing the individual quality on the ball we grew so accustomed to seeing from him consistently during his first stint in Adelaide.
There is a lot of noise surrounding the club right now.
Ben Halloran and possibly Mauk, two players who have been vital to Adelaide's midfield and structure as a whole, are set to depart.
The last thing Veart needs is a club legend, who returned home ahead of this season, failing to justify his big reputation in the City of Churches.
(Other contributors: Christian Marchetti)