Roberto Martínez has given a strong indication that Tim Howard’s Everton career is nearing the end by urging fans to show the USA international “warmth” for the remainder of the season and not to forget his outstanding service at Goodison Park.

The 36-year-old has been linked with a summer return to MLS, in particular Colorado Rapids, after a difficult season at Everton that has at times strained his relationship with the club’s support. Howard is under contract at Goodison until 2018 but with Joel Robles keeping three clean sheets during the veteran’s absence with a knee problem, the former Manchester United goalkeeper may struggle to reclaim the No1 role that has been his for the past decade.

Martínez claims to be unaware of Howard’s future intentions, insisting: “Tim has another two years after this summer so I don’t have to make a decision. I’ve spoken to Tim about everything in general – how he’s feeling about the injury, his thoughts about the national team and how he feels fresh and good. All that matters now is concentrating on the games in front of us. That’s the reality.”

But when asked about Howard’s situation with fans, having attracted ironic cheers when claiming crosses against Leicester and Stoke in December, the Everton manager paid a glowing tribute to the goalkeeper’s 10 years at Goodison and appealed for his contribution not to be forgotten.

“I wouldn’t say there is a lack of respect from the fans,” Martínez said. “We all know football is an emotional game. As a fan you watch your team, you want them to perform well and to win games. You show your emotions and your feelings doing that. I think there is a respect towards Tim for what he has done at Everton over the past 10 seasons. Ten years down the line you’ll be looking back on one of Everton’s greatest goalkeepers and appreciating that he is an ambassador for the club in the way he behaves himself, helping the young players and in his day-to-day approach. He will have that legacy further down the line. I don’t think it is a case of disrespect. It’s just the short-term memory and assessment of what you have seen – that happens, I don’t think that’s being disrespectful.

“This is the tenth season of Tim Howard at Everton and I know that, as a football club, we will have to take a bit of time to consider his best moments and what he has done for this club. We should appreciate that and give him that warmth between now and the end of the season. I think it’s important that Tim doesn’t feel that all his good work has been forgotten.

“That doesn’t take away from the fact that we are emotional watching our football teams, we are judging players for what they are doing and the only action that matters is the last one. That has happened not only to Tim but any player who has represented a big era at a football club. Tim won’t be the last.”

Bryan Oviedo, meanwhile, has signed a new contract until 2019 with Everton. The Costa Rica defender would have been a free agent this summer but has re-signed with the aim, he said, to “win a cup and continue building ourselves into a top Premier League team”.