The British number one has been looking for a permanent coach since splitting from Torben Beltz in the spring and has been trialling Russian Tursunov over the summer.
Raducanu declined to say following her first-round exit at the US Open last week whether she would stick with 39-year-old Tursunov, who reached a high of world number 20 in 2006.
“We had a good six weeks in the States here,” said Raducanu after her defeat by Alize Cornet. “But I haven’t really thought about it.”
However, the PA news agency understands Tursunov will accompany Raducanu to Slovenia, where she has taken a wild card as she looks to begin her climb back up the rankings.
Tursunov has previously had success as a coach with Anett Kontaveit and US Open semi-finalist Aryna Sabalenka, who he guided to the top 10 in an on-off partnership lasting two years.
Sabalenka painted a picture of Tursunov, who was known as a joker during his playing days, as a fiery character, saying: “He’s a good coach, we just had a lot of emotional problems when we were working together but he’s a good coach, he really understands tennis well.
I would say our characters are pretty the same, we are really emotional people, and I need someone who can sometimes step back and breathe.
Aryna Sabalenka on Dmitry Tursunov
“I would say our characters are pretty the same, we are really emotional people, and I need someone who can sometimes step back and breathe. Dmitry was the kind of coach who would start fighting (verbally) with me.
“He’s really good on tactics and he really understands players really well so he can prepare you for the match. He has really good humour and he’s a really funny guy. When he’s not emotional, it’s really a fun time to spend with him.”
Portoroz is on the lowest tier of WTA tournaments but has a relatively strong field, with Wimbledon champion Elena Rybakina and last year’s French Open winner Barbora Krejcikova also signed up.
Speaking after her defeat by Cornet, which will see her ranking fall from 11 to around 83, Raducanu spoke of her desire to seek different experiences.
She said: “The most exciting thing is trying to do well at each of the different tournaments.
“Regardless of what it is, it sounds weird, but, US Open defending champion, obviously it would have been great to defend the title, but I want new experiences. In a way I’ve done that so I want another tournament.
“It doesn’t really matter what it is. I think any player would be happy to win a tournament. I think it makes a massive difference no matter what the level is.”
After Portoroz, Raducanu is due to head to Asia for the Korea Open beginning on September 19.