Euro 2012 Semifinals: Breaking Down X-Factors for Every Team

There are always players that get overlooked when teams make deep runs in major tournaments like Euro 2012.

After all, it's impossible to talk about each player who had an impact on a given game, so the focus is usually on the goal scorers.

As defending champion Spain would attest, it takes an entire team to emerge from the European Championship victorious. La Roja is one of the four teams left standing in this year's event, thanks once again to its remarkable depth.

With that in mind, let's take a look at one player from each semifinal team who will play a key role in his respective match but hasn't been receiving much attention.

Spain: Iker Casillas

Spain hasn't allowed a goal since the group-stage opener against Italy. One of the main reasons for that defensive dominance has been Casillas.

The longtime national time goalkeeper has commanded his box to perfection and has made key stops when necessary.

He'll face a tricky test against Portugal, however.

Real Madrid teammate Cristiano Ronaldo has played with a boatload of confidence over the last couple matches, and that's when he's at his most dangerous. Casillas will have to stay on his toes any time Ronaldo touches the ball.

Casillas has been consistent for so long that it's not a surprise that he probably doesn't get as much recognition as he deserves.

He'll have a chance to earn some praise on Wednesday.

Portugal: Helder Postiga

Ronaldo dominates any headlines related to Portugal, and Nani picks up what's left, but the team will need to get some big performances from depth players to beat Spain.

That starts with Postiga, who has started all four games atop the formation.

Although he scored a goal in the team's victory over Denmark, the veteran striker hasn't made a major impact on the tournament quite yet.

Since La Roja has so much depth and will be focused on stopping Ronaldo, now's the time for him to shine.

Postiga has scored 20 goals in 53 games for the national team, so the offensive ability is clearly there.

He just needs to show it off against the defending Euro champions.

Germany: Mats Hummels

If there were any potential weak link on the German squad heading into the event, it was along the back line. Hummels had very limited international experience, and that usually doesn't bode well on the big stage, particularly for a center back.

The 23-year-old Borussia Dortmund star has proven those concerns unwarranted.

He has been terrific in the middle of the defense and was a major reason the team was able to advance from the group stage with relative ease despite some tough opponents.

Hummels' biggest tests are yet to come, starting with Thursday's match against Italy.

Judging by his play through the first four games, though, German fans have nothing to worry about.

Italy: Antonio Cassano

Italy manager Cesare Prandelli never knows what he can expect from the volatile Mario Balotelli, which means he relies heavily on the more consistent Cassano. He has scored 10 times in 33 appearances for the Italians and has started all of Euro 2012 games so far.

Cassano has only one goal to show for his effort in the tournament, but he has looked dangerous in every match. He's due for a breakout match, and the Azzurri will need one from him in order to take out the vaunted German squad.

While Italy has reached this point by playing sound defense, it will need to generate some offense to keep up with Germany.

That means Cassano has a good chance to steal to spotlight.