JACK Sinclair instantly knew it wasn’t his Achilles, but didn’t realise it was the same mysterious calf injury that the late Liverpool great Diogo Jota sustained in 2022. St Kilda discovered that when they searched far and wide for answers after the co-captain’s season ended in June.

Jota spent more than four months on the sidelines and missed the opportunity to represent Portugal at the World Cup in Qatar. Sinclair tore the lateral and medial tendons in his right calf, plus the soleus against the Western Bulldogs in the opening minutes of the round 15 game at Marvel Stadium.

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Sinclair grew up a devout Liverpool supporter and worshipped former captain Steven Gerrard. Jota and his younger brother tragically died in a car crash just weeks after helping the Reds win the 2024/25 Premier League title. 

St Kilda's high performance team has been in dialogue with a Spanish specialist based in Barcelona who has dealt with roughly 25 different cases of this injury, predominantly in rugby union.

Sinclair won't play again in 2026, but the two-time All-Australian and two-time Trevor Barker Award winner will play a role ahead of Sunday night's crucial encounter against Carlton, which coincides with the sixth edition of Spud's Game.

"The movement probably did look like sort of typical Achilles; I was just jogging back, went to push off, and I just sort of felt all the tension go in my foot and like my soleus just sort of shoot up my leg. I felt my calf straight away and it was rock hard, and then I just could barely walk, so I was pretty confident it wasn't the Achilles," Sinclair told AFL.com.au this week.

"It has been a bit of a slow sort to rehab, but no surgery, which is pretty amazing to think what I felt I didn't need surgery. It was a unique one. I think probably reaching out across the country, hadn't seen a lot of it. So I've sort of found some specialists overseas who've seen it a bit more and a few other different sports. 

"I'm a big soccer fan. So big Liverpool player Diogo Jota did something similar a few years ago and he missed about four months. I suppose that's made it a bit easier [knowing how you make it back]. It's a bit unique, which is like daunting because like, how am I going to go? But to see some guys get back is obviously good."

Sinclair’s calves have always attracted attention on St Kilda’s social media channels for many years. Saints fans froth at them. There is even a dedicated Facebook page in honour of them. 

When we meet this week, Sinclair points out how uneven they currently are. He acknowledges the irony of him doing this injury, but is grateful for how durable he has been, missing only three games due to injury across his 225-game career.

"That's my trademark and has been for a long time since my high school days. Hopefully it comes back all right, but yeah they've [my calves] let me down on this occasion, but that's footy I suppose," Sinclair said.

"I've been so lucky over my career, I've barely missed any footy and I've got a few teammates here who would do everything to probably have the career that I have in terms of how much opportunity I've had with my body. So, of course it's ironic, but I'll get used to them looking a bit different now."

No current player has been at St Kilda longer than Sinclair. When he joined the Saints as a 19-year-old out of Port Melbourne via pick No. 1 in the Rookie Draft at the end of 2014, the club hadn’t returned to its spiritual home. Rowan Marshall and Hunter Clark are the only two players who experienced Seaford. 

Back then Danny Frawley was still holding court in the football department at the Linen House Centre, working with the key position players and making meetings fun like only he could. Sinclair has remained connected to the former St Kilda skipper since his tragic passing in 2019 through his involvement in Spud’s Game with Chelsea Frawley, continuing to promote the importance of mental health conversations. 

"Just check in with someone, you know, it's something that doesn't take much. It's clearly grown so much over the last few years and hopefully it can continue to do so. I think it's just important to keep building the conversation around mental health," he said.

"Any chance I get to represent the Frawley family means a lot to me. I've done a lot of stuff alongside Chelsea over the last few years and I think what they've done since his passing has been just amazing. So any chance I can get involved, I'm more than happy to."

After Jack Steele was traded to Melbourne on deadline day last October, St Kilda ran a leadership process in the pre-season to replace the dual best and fairest winner. The club chose to elevate All-Australian key defender Cal Wilkie and Sinclair as co-captains. 

Wilkie hasn’t missed a game since then – he has played 175 straight since making his debut in round one 2019 – but Sinclair has had to adapt his leadership style in the past six weeks.

"Captaincy was something I never thought I'd be able to do. So to do it alongside 'Wilks' is really exciting. I wouldn't have wanted to do it if I didn't think it'd be good for both of us to sort of share the load. I think in many aspects and the way we operate, we are quite similar in the way we see things. Obviously, both being down back as well, we tend to agree on a lot of stuff, and I think we bounce off each other pretty well," he said.

"But I've definitely had some areas I still want to improve. I think this injury has really forced me to dive into that stuff a bit more, which I've really enjoyed. It’s clearly now a bit of a different look not being out there because I feel like my biggest strength is my performance on game day and sort of leading by example. So to not be able to do that I've sort of had to find other ways to still be a leader when I'm not around here as much."

Sinclair is regarded inside Moorabbin as the benchmark when it comes to preparing for life after football. He finished a business degree a few years ago, spent time interning at Adidas Australia’s head office in Cremorne and more recently spent a day a week at Deloitte on Collins Street. 

"I really enjoyed that" he said. "I rotated through the four teams in mergers and acquisitions, which was good. I've got no idea really what I want to do when I finish footy, so this opportunity came up and I thought it'd be a really good chance to try something new and see if it would be something that I might like to do when I finish my career. So that's kind of what I'm trying to figure out at the moment, just jumping into a few things."

Sinclair is also looking to transform his hobby as a hat maker into a business in the not-too-distant future. It takes him 8-10 hours to make each hat and provides a different outlet from the all-consuming world of football, and there is a demand for them out there.

"It's been a good hobby. I finished uni and I love my gaming, but it's nice to have something else just a bit quieter: just me and the tools and it's very rewarding, I suppose," he said.

"It is a process, but sort of seeing it all come together is really cool. There’s so many options you can do, so many different styles of a hat you can make, so hopefully over the next couple of years, I can dive into that a bit more. I'm working through some branding stuff at the minute, so we might see an unveiling of a of a company in the near future."

Sinclair will be involved in Spud's Game 6 on Sunday for the first AFL and AFLW double header, with both Ross Lyon's men and Nick Dal Santo's women facing Carlton in crucial encounters at opposite ends of their seasons. Memories flood back quickly for Sinclair when picturing Frawley, like has done a lot this week.

"I just remember him doing anything to try and make you laugh, whether it was wrestling with Aaron Hamill out on the training track, or even one time at Moorabbin he rocked up on his motorbike and he started doing doughnuts out on the field, which was just outrageous when we were warming up, like just anything to make you laugh," he said.

"But then on the flip side, sitting in a team meeting, you'd be in the back corner and he'd chime in with some pretty strong feedback to some of our young players about what they needed to do. So you could just tell how passionate he was about the footy club and how much he wanted us to get better."

Twenty-two other men, including Frawley, have captained St Kilda since Darrel Baldock led the Saints all the way sixty years ago. Now Sinclair and Wilkie are carrying the baton to end the wait for the club’s first premiership since 1966.