Major League Soccer's break for Copa America Centenario is finally drawing to a close, as league play resumes for all 20 teams this weekend.

With nearly half the season in the rear-view mirror, a long, hard run to the finish line – the MLS Cup Playoffs in the fall – is about to unfold. Here are a few angles to watch as the action cranks up.

Can LA find – and keep – a groove?

Few clubs in MLS can match the LA Galaxy in terms of star power. It's pretty much always been that way, from Jorge Campos, Cobi Jones & Co. in 1996 to the current edition led by Giovani dos Santos, Robbie Keane and Steven Gerrard. Yet all those shiny pieces still have to fit together into a cohesive whole, and that's been a struggle at times over the past year or so, as our own Matt Doyle has Armchair-Analyzed.

Keane and Gio are both elite players, yet they haven't always been on the same page up top. Gerrard's traits at this point in his career require a careful midfield balance to be crafted around him, and Gyasi Zardes has been shuffled among multiple roles to help make everything work.

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When it all comes together, LA can be unstoppable: They've scored a whopping 20 goals in their five league wins this season. They've also been shut out three times, however, and are just 1-2-3 on the road. Can they find a summer groove? The rest of the league surely hopes not.

Class of '15 tries to graduate

Last year's expansion duo, New York City FC and Orlando City, entered the league brimming with ambition. Both dropped serious coin on big-time players like Kaká, David Villa and Andrea Pirlo, insisting they could outrun the learning curve that makes life so hard for MLS newcomers.

Despite rousing fan support and off-field buzz, both fell short of the playoffs in Year 1. Both have shown promise in 2016, only to let themselves down with a bevy of dropped points at home. Now both NYCFC and the Lions must make up for lost time as they try to secure a spot above the red line in the Eastern Conference.

The first playoff qualification is usually the hardest – just ask Toronto FC.

Timbers, Crew SC try to climb the mountain again

The league's keen competitive balance has always made it difficult to stay on top once you've reached high levels of success. That's why only a handful of teams in its history have ever won back-to-back MLS Cups or even reached the championship final in consecutive years.

Last year's conference champs Portland and Columbus have had no shortage of ups and downs in the early going thus far. The Timbers limped through a five-game winless streak in early spring, followed by a three-match losing skid last month. Meanwhile, three-win Crew SC shipped out their most recognizable star, striker Kei Kamara, to New England after he quarreled with playmaker Federico Higuain in mid-game over a penalty kick on May 8.

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Both sides sit outside the playoff places with losing records at present. Nothing is granted freely when you've got a target on your back.

Is this Dallas' year?

They don't worry much about signing superstars – preferring to grow their own talent at home – and their leader, head coach Oscar Pareja, is a savvy pragmatist who's equally happy beating you with smash-and-grab counterattacking as passing you to death with tiki-taka.

Perhaps that's what makes FC Dallas so dangerous. Spending far less than many glitzier rivals, Pareja has built a program with a clear sense of identity and multiple ways to win. They went agonizingly close to reaching last year's MLS Cup, falling to Portland in a dramatic Western Conference Championship series, and now sit high in both the West and Supporters' Shield standings.

Much will depend on the health and form of their delightful, yet mercurial, Argentine maestro Mauro “The Little Unicorn” Diaz. But FCD are a force to be reckoned with regardless.

Making moves in the transfer market

The league's secondary transfer window opens early next month (July 4), providing teams with the opportunity to bolster their squads on the international market. Some need only a few reinforcements here and there or perhaps the final piece in the puzzle. Others who are less satisfied with their current groups try to make more sweeping changes. A few may even look to sell one of their own talents to an overseas suitor.

It's known as the “silly season,” because it spawns countless rumors, half-truths and fabrications. It also provides ample entertainment for fans, and maybe – just maybe – the missing link that drives their team to a trophy.