Cầu thủ ở đây.

• cầu thủ = player, usually a sports player or athlete
• ở = to be at / to stay at / located at
• đây = here

So the structure is basically:

• cầu thủ → subject
• ở đây → location phrase / predicate

A natural English equivalent is The player is here or The players are here, depending on context.

Vietnamese often does not use a separate verb equivalent to English to be in the same way English does.

In this sentence, ở does the job of expressing location, so Cầu thủ ở đây already means The player is here.

You do not say Cầu thủ là ở đây in normal Vietnamese for this meaning.
Here, là is not needed.

A useful pattern is:

• Subject + ở + place

Examples:

• Tôi ở nhà. = I am at home.
• Anh ấy ở trường. = He is at school.
• Cầu thủ ở đây. = The player is here.

In this sentence, ở marks location. It can often be translated as:

• at
• in
• on
• or more generally to be located

So ở đây means here in the sense of being here / located here.

That is why ở is very common in sentences about where someone or something is:

• Sách ở đâu? = Where is the book?
• Tôi ở Mỹ. = I am in the US.
• Cô ấy ở đây. = She is here.

By itself, cầu thủ does not clearly show singular or plural. Vietnamese nouns usually do not change form for number.

So Cầu thủ ở đây could mean:

• The player is here
• The players are here

Context tells you which one is intended.

If you want to make it clearer, you can add words such as:

• một cầu thủ = one/a player
• các cầu thủ = players
• những cầu thủ = players / some players

Examples:

• Một cầu thủ ở đây. = A player is here.
• Các cầu thủ ở đây. = The players are here.

The normal Vietnamese order is:

• Subject + predicate
• and for location, often Subject + ở + place

So:

• Cầu thủ ở đây = The player is here

This is the standard, neutral order.

You may sometimes see a place phrase moved earlier for emphasis or contrast, but that is less basic and more context-dependent. For a learner, the safest pattern is:

• Ai / cái gì + ở đâu
• who/what + is where

Examples:

• Mẹ ở nhà. = Mom is at home.
• Xe ở ngoài kia. = The car is over there.

Normally, no.
For this meaning, ở is needed.

• Cầu thủ ở đây = correct for The player is here
• Cầu thủ đây = not the normal way to say that

Vietnamese usually needs ở when saying someone or something is in a place.

There are some short expressions in spoken Vietnamese where đây appears without ở, but they are different structures, not the basic location sentence you are learning here.

A rough pronunciation guide for English speakers is:

• cầu ≈ guhw / kuh-oo said with a falling tone
• thủ ≈ too with a dipping-rising tone
• ở ≈ a short vowel something like uh with a creaky/rising quality
• đây ≈ day with a level or slightly rising sound depending on accent

A few helpful notes:

• cầu has the huyền tone
• thủ has the hỏi tone
• ở has the hỏi tone
• đây has the ngang tone

Also:

• th in Vietnamese is an aspirated sound, not the English th in think
• đ is like English d
• final rhythm is usually smooth and natural: Cầu thủ | ở đây

If you are learning Northern Vietnamese, the tones and vowel quality will sound a bit different from Southern Vietnamese, but the sentence structure is the same.

Usually cầu thủ means a sports player, especially in contexts like football/soccer, basketball, and similar sports.

It does not usually mean a game player in the broad English sense, such as:

• a chess player
• a video game player
• a music player device

For those, Vietnamese often uses different words depending on context.

So in Cầu thủ ở đây, a learner should understand cầu thủ as an athlete/player on a team or in a sport.

Vietnamese often relies on context, so bare cầu thủ can already mean the player if the listener knows which player you mean.

If you want to be more explicit, you can say:

• cầu thủ này = this player
• cầu thủ đó / cầu thủ đấy = that player
• cầu thủ kia = that player over there

Examples:

• Cầu thủ này ở đây. = This player is here.
• Cầu thủ đó ở đây. = That player is here.

So in your original sentence, cầu thủ may be interpreted as the player simply because the context already identifies the person.

These words all relate to location, but they point to different distances or discourse contexts.

• đây = here, near the speaker
• đó / đấy = there, often not right next to the speaker
• kia = over there, usually farther away or more clearly separated

So:

• Cầu thủ ở đây. = The player is here.
• Cầu thủ ở đó. = The player is there.
• Cầu thủ ở kia. = The player is over there.

The exact feeling of đó vs đấy can vary by region and speaking style, but for beginners, both are often understood as there.