Signed by former Saints boss Nigel Adkins last summer from Dutch side VVV-Venlo, the 24-year-old has since blossomed into a first-choice centre-back for current manager Mauricio Pochettino.
But it could have been very different after a debut to forget against Arsenal in September.
Yoshida replaced the injured Jos Hooiveld with the score at 1-0 to the Gunners, who then moved up through the gears, recording an emphatic 6-1 victory with the former Nagoya Grampus man partly at fault for the third goal.
After forming part of the Japan squad at the 2012 Olympics, Yoahida was thrown into the Premier League after just one training session with his Southampton team-mates.
But he has adapted since then and will be one of the first names on Pochettino's team-sheet for the visit of West Brom on Saturday.
Recalling his debut, Yoshida admitted he did not think he would get a chance in the first team so early into his career in England but has enjoyed his run in the side since that forgetful day at the Emirates.
"To be honest I didn't expect to get a big chance so early," he said. "I was hoping I could get a really big chance against Arsenal but after then I have kept playing well until now.
"Playing football is the most important thing and I'm very grateful to Nigel and Mauricio so I will just keep going.
"We vave played well, are organised defensively and when we are attacking we show good risk management with Corky [Jack Cork] and Morgan [Schneiderlin] playing very well."
- Sports & Recreation
- Mauricio Pochettino
- Jos Hooiveld