Andrei se alătură echipei în loc să joace.

The dictionary form is a se alătura, meaning to join.

In this sentence, se alătură is:

• 3rd person singular
• present tense

So Andrei se alătură means Andrei joins or Andrei is joining. Romanian present tense can often cover both ideas, depending on context.

Not necessarily. Here, se is part of the verb a se alătura. It is a pronominal/reflexive-type verb, but in English you usually do not translate se literally.

So:

• a se alătura = to join
• you normally cannot just drop se in this meaning

In fact, a alătura without se is a different verb, more like to place/add something next to something else.

Because a se alătura usually takes the dative case: a se alătura cuiva = to join someone/something.

So:

• echipa = the team as a basic subject/direct-object form
• echipei = to the team

That is why the sentence has se alătură echipei.

Here it means the team.

Compare:

• unei echipe = to a team
• echipei = to the team

Romanian often puts the definite article at the end of the noun, and in forms like dative/genitive feminine singular, that gives -ei here: echipei.

În loc să is a common structure meaning instead of or rather than when it is followed by a verb.

So:

• în loc să joace = instead of playing

A useful contrast:

• în loc să
  • verb
• în loc de
  • noun

For example:

• în loc să joace = instead of playing
• în loc de fotbal = instead of football

Because after în loc să, Romanian uses the subjunctive.

The subjunctive is usually formed with:

• să
  • a special verb form

For a juca:

• joacă = present indicative, plays/is playing
• să joace = present subjunctive, used after triggers like în loc să

So în loc să joace is the correct structure here.

It is understood to be Andrei.

So the sentence means that Andrei joins the team instead of playing. Romanian often leaves the subject of the second verb unstated when it is clear from context.

If the second action had a different subject, Romanian would usually make that clearer with a different structure.

A rough pronunciation guide is:

An-DRAY se a-lə-TU-rə e-KI-pey în lok sə JOA-che

A few helpful sound notes:

• ă in alătură and să sounds like the a in sofa
• î in în has no exact English equivalent; it is a central vowel
• ce in joace sounds like che in check, but with a clearer e sound at the end

Yes, Romanian word order is fairly flexible, but Andrei se alătură echipei în loc să joace is a very natural order.

The most important parts to keep together are:

• se alătură
• echipei
• în loc să joace

You might move things around for emphasis in some contexts, but the version given is neutral and standard.