The French defender has not featured for the club since the turn of the year, having been sidelined by a hamstring problem.
But Martinez revealed on Thursday that Distin had been able to train normally with no recurrence of his injury.
"Sylvain has come through four sessions now and has had no reaction," he told the club's official website. "That, straight away, has been one of the benefits.
"He has been able to work with the group with no effects to him."
The Spaniard was also delighted that his squad was reaping the benefits of attending the mid-season training camp.
"It has been terrific so far," Martinez added. "It has been a unique opportunity to spend a lot of time together and to work on the training pitch.
"The players have benefited because of the humidity and the weather. We have been working hard and getting the benefits from it.
"The boys who are carrying a little bit of an injury or a problem have been able to work extra time and it’s been very beneficial for the whole team."
Everton travel to The Hawthorns to face West Brom in the Premier League on Monday.
‘He instantly popped into our ratings as one of the best U21 midfielders in Europe. The impressive thing is Slot has made him into more of a no.6' Inside Ryan Gravenberch's transformation at Liverpool
‘I don’t think Liverpool would look at Ollie Watkins, a striker isn’t a pressing issue for them – it’s Arsenal who need one’ Former Reds star explains why his old club don’t need an out-and-out forward this summer
