LIVERPOOL -- Everton midfielder Bryan Oviedo will miss the rest of the Premier League season -- and Costa Rica's Gold Cup campaign -- with a broken bone in his right foot.
Oviedo fractured the fifth metatarsal in his foot during a training session, manager Roberto Martinez said.
The 25-year-old had only just returned to training after more than two months out with a hamstring injury.
He had been scheduled to feature as an overage player in Everton's under-21 Premier League match against Liverpool at Goodison Park on Thursday evening.
Martinez told a news conference: "It was a very unfortunate action on his own. He was trying to get on the ball and his ankle rolled in a very awkward position.
"Bryan's going to be out for the rest of the season and he's going to miss playing with Costa Rica in the Gold Cup.
"He should be back for the end of preseason as we see it now. If he misses some pre-season, we need to make sure that he gets that work done."
Oviedo, who joined Everton from FC Copenhagen in August 2012, has endured a series of injury misfortunes in the last 18 months.
He missed last year's World Cup in Brazil after breaking his leg during Everton's FA Cup fourth-round win at Stevenage in January 2014.
The midfielder made his comeback in a Capital One Cup defeat at Swansea the following September, but has made only two Premier League starts since then.
Oviedo had been hoping to play a part for Costa Rica at the Gold Cup in Canada and the United States this July.
Martinez added: "He knew straight away that he had done something really bad. As a player, you understand if it's only a knock or something a bit more serious.
"It took him a couple of hours to get his head around it -- and then straightaway, it was incredible how positive he was.
"He wanted to know what the next step was. I would say that, mentally, he is in a great place. He is desperate to get back and fully fit.
"We're talking about the week that he was ready to join the squad. He was ready to play the Under-21 game tonight at Goodison. So it was a very significant moment in trying to get his season back to normal."
Martinez insists that his focus is now on ensuring Everton continue a strong run of form that has seen them pick up 16 points from the last 18 available.
That sequence of results, which included a 3-0 win over Manchester United last Sunday, has lifted Martinez's side into the top half of the table ahead of Saturday's trip to Aston Villa.
Everton's manager has to sort out the futures of several members of his squad; including out-of-contract defenders Luke Garbutt, Antolin Alcaraz and Sylvain Distin.
Alcaraz and Distin are not expected to get new deals, but Martinez is hopeful that England under-21 international Garbutt will stay.
The manager said: "I don't see the contract situation as a big issue. If Luke Garbutt wants to stay at Everton, then we want him to stay.
"It's something we'll have to go through at the end of the season."
Martinez is monitoring Manchester United winger Adnan Januzaj ahead of the summer transfer window, but is only likely to make a move if he does not sign Aaron Lennon permanently.
Lennon is on loan from Tottenham, and Everton's manager said that discussions over the 28-year-old's future will take place at the end of the season.
He said: "Nothing's changed with Aaron. We're going to leave that conversation until the end of the season.
"As it happens, the last game of the season is one that Aaron cannot participate in. I'm sure that will be the period when we're able to address the situation.
"That's about sitting down with Aaron, thanking him for his efforts and seeing how he feels. From that point on, it's a three-way conversation, and we'll see where that takes us."
Everton's final game of the season is at home to Tottenham, and Lennon will be ineligible to face his parent club under Premier League rules.