When Hamburg were beaten 9-2 by Bayern Munich, Rincon led the game in free-kicks conceded (five), and he only played 57 minutes.
Rincon's fouls per game since the 2009-10 season have ranged from 1.4 to 2.9, so he is always playing on the edge. This was illustrated in the 3-2 defeat to Mainz, as 16 minutes separated Rincon's first and second yellow card.
He was sent off by referee Bastian Dankert in the 82nd minute with the score tied at 2-2. Mainz pushed on with a one-man advantage and Shinji Okazaki scored a stoppage-time winner.
The impact Rincon has on games is dependent on how lenient the referee is on the day. Lax officiating enables him to accumulate easy tackles. Strict officiating limits any meaningful influence Rincon can have.
This would explain why 43 percent of Rincon's games are sub-affected at Hamburg.
The strategy of taking him off before he does damage works because the red card against Mainz was his first in the Bundesliga.
The concern Cardiff manager Ole Gunnar Solskjaer should hold is Rincon's tackle success percentage drastically dropping from 86 last season to 45 this season.
His tackling inefficiency is reflected in his Kicker player rating.
On a scale of one to six, one being the best and six being the worst, his player rating is 4.56, so he is Hamburg's 18th-best-ranked player this season, per Kicker.
Another worry for Cardiff management is Rincon's tendency to play out from the back.
He received the ball outside of his penalty box, and his first instinct was to turn and charge forward. He spun straight into Hannover left attacking midfielder Szabolcs Huszti, who stole the ball and scored.
Can Rincon keep up with the intensity of the Premier League?
What Rincon Brings to Cardiff
Rincon is a tough, gritty and robust midfielder.
His 3.6 tackles per game are 0.9 more than Cardiff right-back Kevin Theophile-Catherine, who leads the club in TPG (2.7) this season.
Rincon not only can play in midfield but has filled in at right-back, so Solskjaer is covered if Theophile-Catherine and Kevin McNaughton are out.
Paul Abbandonato at Wales Online suggested that Solskjaer should move midfield anchor Gary Medel to centre-back, the position he plays for the Chilean national team.
In that scenario, it makes sense why Rincon would be signed, because he would fill Medel's void.
As long as Rincon improves his tackle success rate and is error-free, he will not fail Solskjaer.