Saigrač je obećao da će doneti grickalice.

je is the auxiliary verb used to form the Serbian past tense.

So je obećao = promised.

More literally:

• je = is/has as an auxiliary
• obećao = past participle of obećati (to promise)

Serbian commonly forms the past tense with:

• a form of biti (to be)
• plus a past participle

So:

• On je obećao = He promised
• Ona je obećala = She promised

Because obećao is the form needed for past tense, while obećati is the dictionary form / infinitive.

Compare:

• obećati = to promise
• obećao = promised (masculine singular)
• obećala = promised (feminine singular)

Since the sentence is talking about something the teammate already did — he made the promise — Serbian uses the past form obećao.

That ending agrees with the subject.

Here, saigrač is a masculine singular noun, so the participle is also masculine singular:

• saigrač je obećao = a male teammate promised

If the subject were feminine, you would get:

• saigračica je obećala

If plural:

• saigrači su obećali
• saigračice su obećale

So the ending on obećao tells you about the gender and number of the subject.

It is a subordinate clause that expresses what was promised.

Literally, it is something like:

• promised that he would bring snacks

In Serbian, after verbs like obećati (to promise), it is very common to use:

• da
  • a verb clause

So:

• obećao da će doneti = promised that he would bring

English often prefers promised to bring, but Serbian usually uses a full clause here.

In this sentence, da is closest to that in structure.

A very literal breakdown would be:

• Saigrač je obećao da će doneti grickalice.
• The teammate promised that he would bring snacks.

But in natural English, we often say:

• The teammate promised to bring snacks.

So even if the natural translation uses to bring, the Serbian grammar here is built more like that he will bring.

Because after da, Serbian normally uses the future as:

• da će + infinitive

So:

• da će doneti = that he will bring

In an independent main clause, you could say:

• Doneće grickalice. = He will bring snacks.

But after da, the form da će doneti is the expected pattern.

Because će is a clitic — an unstressed word that has special word-order rules.

In Serbian, clitics usually come in the second position of their clause. In the subordinate clause here, da comes first, so the clitic će goes right after it:

• da će doneti

This is normal Serbian word order.

In this sentence, the default interpretation is that the teammate is also the one who will bring the snacks.

So the understood meaning is:

• The teammate promised that he would bring snacks.

Because the subject of the second clause is not stated separately, Serbian normally assumes it is the same person unless context suggests otherwise.

If you wanted to make a different subject explicit, you would normally say it:

• Saigrač je obećao da će Marko doneti grickalice.
• The teammate promised that Marko would bring snacks.

This is a question of aspect, which is very important in Serbian.

• doneti = perfective
• donositi = imperfective

Here, doneti is used because the sentence refers to one complete future action: bringing the snacks.

So:

• će doneti grickalice = will bring the snacks / will bring snacks as a completed act

If you used donositi, it would sound more like repeated, habitual, or ongoing bringing, which does not fit as well here.

It is in the accusative plural, because it is the direct object of doneti.

The verb doneti takes an object:

• bring what?
• grickalice

For many feminine nouns in the plural, the nominative plural and accusative plural look the same, so grickalice can look unchanged even though it is functioning as an object here.

You usually know from context, because Serbian has no articles like a or the.

So saigrač by itself can correspond to:

• a teammate
• the teammate

The surrounding situation tells you which one is meant.

That is very normal in Serbian.

The form saigrač is grammatically masculine singular.

So in ordinary usage, it usually refers to a male teammate.
The feminine form would be:

• saigračica

However, in some contexts, masculine forms can be used more generally, but if you clearly mean a female teammate, Serbian would normally use the feminine noun.

It is built from:

• sa- = with / co-
• igrač = player

So saigrač literally means something like co-player, which naturally corresponds to teammate in English.

It is a very useful everyday sports/team word.

Not completely. Serbian word order is fairly flexible, but the clitic je has to follow clitic-placement rules.

The neutral order here is:

• Saigrač je obećao...

You might also see different orders for emphasis, but the given sentence is the most straightforward and natural neutral phrasing.

So for a learner, Saigrač je obećao da će doneti grickalice is a very good standard model to remember.