Tim Howard 'very important' - Everton manager Roberto Martinez

LIVERPOOL -- Everton manager Roberto Martinez insists he is standing by Tim Howard even though Joel Robles will play in Tuesday's Capital One Cup quarterfinal at Middlesbrough.

Robles has deputised for the U.S. international in each of the Toffees' cup matches so far this season, and will continue to do so.

Howard came in for criticism over his positioning as Junior Stanislas scored a dramatic equaliser for Bournemouth in a 3-3 Premier League draw on Saturday. Martinez says that the goal was not his keeper's fault, though, indicating that Howard will return for the home league match against Crystal Palace next Monday.

Robles was outstanding as Everton beat Norwich on penalties in the last round of the Capital One Cup, and has his manager's support to repeat the trick on Tuesday.

Martinez said: "In this competition, Joel was man of the match in the last round and he's going to start tomorrow. That's something that's been planned.

"Since he came back into the side after the previous round, Tim has been very consistent performing with a real influence on the back four and the rest of the team.

"The third goal at Bournemouth was a disappointment, because it was the last kick of the game. But as a team, we should have done a lot better, and not just rely on the goalkeeper.

"The ball should never get into that position. When someone has a free header just outside the six yard box, there's a real question about the marking.

"That's something we have to learn. As a young team, sometimes those moments can surprise you. I don't think it was an individual error at all."

Robles has largely been restricted to cup appearances since joining Everton from Atletico Madrid in 2013 following a loan spell at Wigan, where he played for Martinez. But the Everton boss believes that he has room in his squad for both goalkeepers.

He said: "I think in the modern game, gone are the days when you only have one goalkeeper. You need to have two very good number ones, two goalkeepers who can both play different roles.

"Tim Howard is an incredible source of experience and can give direction to the young players. At his age, and given the number of games he's played for Everton, he's a very, very important player for us.

"Joel has the potential to be a very special goalkeeper. That's why we brought him to the club. There is competition for places.

"It's been very important for Joel to play in the League Cup this season. He showed a very good level, especially against Norwich in that penalty shoot-out, where you're going to be tested on mentality and temperament.

"They're both very important, and there will be moments when we need them both. We need a squad with two very strong goalkeepers."

Midfielders James McCarthy and Gareth Barry are both doubts for the match at Middlesbrough. McCarthy came off during the Bournemouth match with a hip problem, while Barry suffered a shin injury.

Martinez said: "We'll have a clearer picture today. James had to come off during the game. He overextended his upper hip muscle, a little bit higher than the groin area.

"Yesterday, he was quite sore. We'll find out a bit more today. It's exactly the same with Gareth Barry. He had a really nasty knock to the shin. There were stud marks there. He was finding it really difficult to walk yesterday.

"Those two players will have to be assessed before we name the squad."

Left-back Leighton Baines is likely to be involved in the squad, having finally recovered from two ankle injuries that have kept him out of action since May.