Stan Wawrinka has identified Roger Federer's former coach Paul Annacone as a contender to work with him on a full-time basis after Magnus Norman gave up the role in October.
During four years together, Wawrinka won three grand slam titles, but Norman opted to call time on the relationship citing family reasons.
The decision took Wawrinka, 32, by surprise and leaves him seeking a new coach just weeks before the start of the 2018 season.
And the Swiss right-hander has not ruled out enlisting Annacone, who worked with him at Wimbledon this year and previously has guided both Federer and Pete Sampras to multiple grand slam singles titles.
"It was a great disappointment for me, a shock, in some moments of your career, you expect to be able to count with your closest ones, and the time he announced it surprised me," Wawrinka admitted to reporters.
"And who will be my new coach? At this point, I'm still with Yannick Fattebert, and I will need somebody for long-term cooperation, for at least three to four years. I have some names on the list. Yes, Paul Annacone is on the coach list but I have not made a decision yet. "I do not know if this will happen, because his agenda is busy."
Wawrinka joined a stellar cast of players to withdraw from the closing months of the season after surgery on a knee injury suffered in 2016. Andy Murray, Novak Djokovic and Milos Raonic also missed the closing months of the season, but Wawrinka wants to join them in returning at the Australian Open in January.
"It has been a year, since 2016 Swiss Indoors in Basel, that I suffered knee issues," he added. "The only regret is that I didn't stop before the grass-courts season, which worsened the situation. At the moment my priority is to recover well from the two surgeries I had.
"My knee is a little bit strict. I work hard physically six days on seven, but from the tennis point of view I am a little bit behind. The goal is to play Australian Open, even if I am not 100% healthy. Having had crutches was hard, but the break allowed me to take a rest mentally after years where I was always at the limit."