The United States international has been sidelined since being replaced at half-time in the Premier League clash with Stoke City on Boxing Day.
Howard is set to return next month and Martinez on Wednesday stated that the former Manchester United keeper could be back sooner than he anticipated.
He told the club's official website: "Tim is progressing really well, better than any medical advice would think.
"We are still working within those six to eight weeks since the injury happened but he is progressing extremely well and probably a little bit ahead of what we predicted.
"We are now going to carry on treating him based on how he feels each day."
Martinez believes a trip to Qatar has proved to be beneficial for a number of players who have been in the treatment room, with James McCarthy and Sylvain Distin possibly returning for Saturday's trip to Crystal Palace.
The Spaniard said: "It was a chance to regenerate the bodies. We saw Darron Gibson adapting well with the group, as did Sylvain Distin.
"Sylvain has benefitted a lot by being able to work in the warm weather, so we expect that he will be available to make the squad for Saturday.
"James McCarthy, in the same way, put in a lot of good work and in the next 48 hours we will know whether he will available to make the Crystal Palace game. I would be positive in saying James will be back in the squad very soon.
"Leon Osman and Steven Pienaar have a little bit of a longer term of rehabilitation. They have been progressing well and working hard individually. We will see how quickly they can recover but it is a bit of a longer period for them."
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