Η φανέλα της παίκτριας είναι μπλε και άσπρη.

Because Greek uses the genitive case to show possession.

• η παίκτρια = the player (subject form / nominative)
• της παίκτριας = of the player / the player's (genitive)

So in this sentence, της παίκτριας tells you who the jersey belongs to: the player's jersey.

There are two different cases here:

• Η φανέλα is in the nominative, because it is the subject of the sentence.
• της παίκτριας is in the genitive, because it shows possession.

So the structure is basically:

• Η φανέλα = the jersey
• της παίκτριας = of the player

The dictionary form is παίκτρια. That is the nominative singular.

When this noun goes into the genitive singular, it becomes παίκτριας.

So:

• η παίκτρια = the player
• της παίκτριας = of the player / the player's

This is a very common pattern for feminine nouns ending in -α.

Because Greek uses the definite article more often than English does.

Here:

• Η φανέλα = the jersey
• της παίκτριας = of the player

In English, we often just say the player's jersey, but Greek normally keeps the article with the possessed noun and also with the possessor in the genitive.

So η ... της ... is a very normal Greek pattern.

είναι is the present-tense form of είμαι (to be) used for he / she / it is.

The subject is Η φανέλα (the jersey), which is singular, so Greek uses είναι:

• Η φανέλα είναι... = The jersey is...

Unlike some Greek verb forms, είναι is the same for all persons in the plural and also for the 3rd person singular, so you simply learn it as the standard present form of to be.

Because άσπρη is a regular adjective that agrees with the noun, while μπλε is usually indeclinable.

• φανέλα is feminine singular
• so άσπρος becomes άσπρη to match it

But μπλε usually stays μπλε no matter what noun it describes.

So:

• μπλε φανέλα
• μπλε παπούτσια
• μπλε παίκτης
  all keep μπλε

But άσπρος changes:

• άσπρος (masculine)
• άσπρη (feminine)
• άσπρο (neuter)

Because the noun it describes, φανέλα, is feminine singular.

Greek adjectives usually agree with the noun in:

• gender
• number
• case

So here the correct form is:

• η φανέλα → feminine singular
• therefore άσπρη

If the noun were masculine, you would use άσπρος.
If it were neuter, you would use άσπρο.

No. Another very common word is λευκή (from λευκός).

Both can mean white, but they do not always feel exactly the same:

• άσπρος / άσπρη / άσπρο = very common, everyday word
• λευκός / λευκή / λευκό = also common, sometimes a bit more formal or stylistically neutral depending on context

So you could also hear:

• Η φανέλα της παίκτριας είναι μπλε και λευκή.

That would also be correct.

In this sentence, φανέλα means something like jersey or shirt, especially in a sports context.

Depending on context, φανέλα can also mean:

• an undershirt
• a sleeveless shirt
• a team jersey

Because the sentence mentions the player, the sports meaning (jersey) is the most natural one here.

Yes, Greek word order is more flexible than English word order, but the version you have is the most neutral and natural:

• Η φανέλα της παίκτριας είναι μπλε και άσπρη.

You may also hear:

• Της παίκτριας η φανέλα είναι μπλε και άσπρη.

That puts more emphasis on the player's.

But for a learner, the original order is the safest one to use.

Yes. If you say:

• Η φανέλα της παίκτριας είναι άσπρη και μπλε.

that is also grammatically correct.

The difference is mainly about emphasis or the order in which the colors are presented, not basic grammar.

A rough pronunciation is:

ee fa-NE-la tees PEK-tree-as EE-ne bleh keh A-spree

A few useful pronunciation points:

• Η sounds like ee
• αι in παίκτριας sounds like e
• μπ at the beginning of a word is pronounced like b
• ει sounds like ee
• the accent mark shows the stressed syllable:
  • φανέλα
  • παίκτριας
  • είναι
  • άσπρη

Yes, here και simply means and.

It joins the two color adjectives:

• μπλε και άσπρη = blue and white

In pronunciation, και is often said like ke in normal speech.