Boro boss Gordon Strachan will spend the next few months tinkering with his squad in the hope of assembling a pool of players capable of delivering promotion this time next year.
French striker Jeremie Aliadiere has already decided he will leave at the end of his contract next month, while Emanuel Pogatetz, Jonathan Grounds, Chris Riggott and Chris Killen are all to discuss new deals.
Even if Pogatetz and Riggott agree to take significant pay cuts to extend their stay on Teesside, there are still likely to be a number of changes before the transfer window closes at the end of August.
Arca, who played 24 times under Strachan before heading back to Argentina for a three week break, has conceded the close-season will be an uncertain period.
I don't know what will happen. Some players are running out of contract, others will want to try a new experience elsewhere, said Arca. It happens everywhere and I'm sure it's going to happen here as well.
The manager will want to bring in his own faces because he will want to make this situation better. It will change, I won't lie.
I still have another year on my contract. I just have to wait to see what the club will do.
If they are looking to bring in new faces and get rid of some old faces then I will just have to see. But I will keep working and I'm still a Middlesbrough player. It's up to them what they want to do.
Arca will return from his South American break to the North-East in time to fly out to La Manga with the rest of the squad on May 22, when Strachan will put his players through their paces at a training camp.
The Boro boss has been quite open about his intentions to improve his squad's fitness and players' mentalities dramatically before the start of the second campaign in the Championship.
Arca, Gareth Southgate's first signing in 2006 after five years with Sunderland, has already had a taste of things to come on the training ground, but feels Strachan will be keen to avoid premature burnout before a competitive ball has even been kicked.
We are all expecting to work hard, the manager has said that for a few weeks, said Arca. It will be hard work but pre-season is always hard.
With some managers it's harder than others.
Some players who were with him at Celtic will know, but there rest of us don't know. Last year was hard under Gareth but it was good.
We were working hard and started fresh at the beginning of the season.
The manager will know what he wants to do, because he will also be keen to make sure we are fresh and fit for the start of the season, so we can't overdo it. We know it will be harder this summer.
Meanwhile, Boro duo Brad Jones and Rhys Williams will discover their fate when Australia boss Pim Verbeek names his provisional 27-man World Cup squad today.
Scott McDonald is guaranteed to make the squad, but Jones is one of five goalkeepers battling for a place behind Mark Schwarzer while Williams spent the final month of the season struggling with a pelvic problem.