Over the next four months, we'll be giving you the lowdown on the star names we feel pose the biggest threat to the Lions' hopes of a first series victory in 16 years, and we'll be asking you for your thoughts and suggestions on facebook and twitter.
Some of the players we highlight will already be household names but others will be bolts from the blue, youngsters yet to cement a starting spot or experienced club campaigners peaking at just the right time to achieve the ultimate goal this summer.
Horwill undoubtedly falls into the first of those categories, but his injury situation means he has plenty of work to do to be at his best by the time of the first Test in Brisbane on June 22.
The 27-year-old hasn't played for club or country for nine months now after tearing his hamstring in May of last year. Horwill limped out of the Reds' defence of their Super XV title three quarters of the way through the domestic season and hasn't worn the Green and Gold of Australia since the end of the previous year as a result.
He missed the summer Tests with Scotland and Wales, the entire Rugby Championship campaign, the third Bledisloe Cup clash with New Zealand and the recent tour of Europe and still isn't ready to return to action.
A minor ankle injury picked up in pre-season training meant he was unavailable for the tournament opener with the Brumbies and he will again sit out the second round tie with the Waratahs despite initially being tipped to make his comeback from his hamstring troubles in the friendly win over the Chiefs a fortnight ago.
Wallaby head coach Robbie Deans clearly has great faith in the 6ft 7in second row, though, and we expect him to be leading the charge against the Lions once he's back to full fitness.
Deans promoted Horwill to national captain prior to the Tri Nations decider against New Zealand in August of 2011 and there's no reason to think he'll lose the armband if he stays injury free from now on. Australia were then on the verge of a first tournament success in a decade but Deans dumped incumbent skipper Rocky Elsom after deciding Horwill was the man to guide his team to glory and it would take a big change of heart for him to suffer a similar fate to his predecessor.
Horwill's first involvement as skipper saw the Wallabies crowned kings of the southern hemisphere but the success story soured when Ireland upset the apple cart with a shock victory in the pool stages of the World Cup in mid-September of that year. The end result of that surprise reverse was a semi-final exit at the hands of the All Blacks but there were few calls for Horwill's head and Deans was never going to make his main man a scapegoat.
James Horwill captained Australia at the 2011 World Cup but has been dogged by injury since May 2012
Deans rates his right-hand man highly - as do the majority of the Australian rugby public - but Horwill is far from the most experienced member of the Wallaby set up. He made his Test debut against Fiji in Perth in 2007 but has since seen his international career affected by serious injury on three separate occasions. In addition to his latest lengthy absence, Horwill missed a large part of the 2008 Test calendar with a foot problem and was then forced to sit out the entire 2010 campaign with knee damage.
As well as limiting his number of Test caps, those setbacks have meant Horwill is far less well-known - and far less appreciated - in the northern hemisphere than he otherwise might have been. But while his promotion to captain of his country may have come as somewhat of a shock in terms of its timing, his value to the Wallabies should not be underestimated.
Prior to being rested for the defeat to Samoa the summer before last, Horwill had started every match for which he had been available since 2008. He was the only member of the Wallaby squad to begin all 14 internationals in 2009 and was recalled straight back into the starting XV when he recovered from the second of those serious injuries.
He enjoys a similarly exalted status in Super Rugby, having played in 39 straight games for the Reds before his foot issues four years ago. He has since been a pivotal figure in the Reds' recent success, marking his return from his knee problem by captaining them to a title-winning campaign two years back.
Horwill was at the helm as the Queenslanders secured a first Super Rugby crown since 1995, providing a steely focus to the Reds' surge to the top of the regular-season table. And while the likes of Quade Cooper and Will Genia took most of the plaudits for that particular triumph, Horwill's abrasive nature in the loose and his calmness and composure under pressure was key in ensuring Ewen McKenzie's men saw off perennial champions the Crusaders in the final at the Suncorp Stadium.
So just what is it that makes Horwill such a vital figure for club and country? Well, first up there's his sheer physical presence. The Wallabies may be known as thinkers rather than fighters but Horwill is their sternest enforcer. He may not be in the same mold as a Martin Johnson or a Bakkies Botha but he's no pushover. And while a knock on the dressing room door is unlikely to strike fear into the most brutal of opponents, you can guarantee that Horwill will never take a backward step. Looks can be deceptive and, in short, he is the Wallabies' hard man, a defiant defender of his realm and a player who isn't afraid to go toe-to-toe with anyone in world rugby.
Then there's his leadership qualities. Ask any of his Reds or Wallabies team-mates and they'll all say the same thing: Horwill is the kind of guy you just love playing for. He inspires a 'we're all in this together' and 'we can achieve whatever we want to achieve' attitude with his no nonsense 'I'll lead and you follow' style of captaincy. He's well spoken and intelligent yet he leads by example and his actions still speak louder than his words. He does exactly what he says he'll do and that encourages others to do the same.
He's an impressive ball carrier and nearly always gets his team over the gain line. He makes the hard yards on a regular basis and is always looking to get involved in the loose without seeking glory out wide. He hits rucks, is a powerful force in the driving maul and does all the dirty work. The likes of Cooper, Kurtley Beale and James O'Connor may be set to grab the headlines this summer but it's Horwill who will set the platform for them to shine.
Horwill is likely to be under the media spotlight before and during the Lions tour this summer
On the field he's a hard man but off it he's a hard man to dislike. Comfortable with the media and bright enough to get his points across without being ruffled by reporters, Horwill is already proving a great promoter for the Lions tour. He happily gives journos the amount of copy they require; shows plenty of respect for the heritage and quality of Britain and Ireland's elite; and he's regularly reminding the Australian public of their role in backing their boys.
He does have one identifiable weakness, however, and it comes in the shape of the lineout. There's no suggestion that he's a liability in this area - you couldn't be a world-class second row without grasping the setpiece - it's just that he's not the dominant force he could be.
Instead of taking a lead here, he appears more comfortable playing second fiddle to the likes of Nathan Sharpe. Whenever veteran Sharpe pulled on a Wallaby jersey alongside his skipper, the Wallaby lineout tended to be solid enough. When Sharpe wasn't around, it had a tendency to struggle. Horwill seemed to thrive when his second-row partner took control of that area but, with Sharpe having now retired, it looks like Horwill will need to develop an extra edge before the Lions arrive Down Under.
Name: James Horwill
Date of birth: 29/05/1985
Position: Second row
Height: 6ft 7in
Weight: 18 stone 2lbs
Test debut: Versus Fiji in Perth, June 2007
Test caps: 35 (as of 21/02/2013)
Strengths and weaknesses
Strengths: physicality, hard graft and a determination to get over the gain line, all coupled with an innate ability to inspire.
Weaknesses: a lack of command at the lineout and an unfortunate attraction to long-term injury.
Chances of being involved against the Lions: an odds-on-favourite for a starting spot unless fate continues to cruelly intervene. Unlikely to be pushed out by anyone other than bad luck.
Rivals for the Wallaby shirt
In truth, injury is Horwill's biggest rival. Underperform and he may miss out but it really is unlikely unless his body fails to recover, or gives way again, before the summer.
Sharpe was an outstanding servant to Australian Rugby for a more than a century of Tests but his decision to finally call it a day at the end of 2012 leaves a big gap in the Wallaby boilerhouse. Dan Vickerman was another stalwart with the potential to keep Horwill out of the Test team but his injury-enforced retirement means experience is at a premium when it comes to second row contenders.
The Wallabies' horrific run of injuries may have seen a host of youngsters and Test newcomers step into the limelight over the past year but none are anywhere near Horwill's stature just yet.
Waratahs duo Sitaleki Timani and Kane Douglas are the front runners to join Horwill in the starting side but it is likely that they or the likes of Cadeyrn Neville, Hugh Pyle, Hugh McMeniman and Rob Simmons will be battling it out to play alongside, rather than instead of, their skipper.
Sitaleki Timani has impressed for the Wallabies in Horwill's absence
Tongan-born Timani impressed with his physicality and effectiveness in the loose on the tour of Europe and now has nine caps to his name having made his debut in defeat to Samoa in the summer of 2011. He still has someway to go to polish his skills in the setpiece but his raw power offers the Wallabies a potent attacking threat.
Timani started two of the four Tests in November and December of last year, with Douglas packing down next to Sharpe in the other two. Douglas only made his Test bow in the encounter with Argentina on the Gold Coast but went on to feature in the three remaining Rugby Championship fixtures, the third Bledisloe Cup clash and then against France and Wales.
Like Timani, 23-year-old Douglas lacks experience at international level but he showed enough at the back end of 2012 to prove he is comfortable with the step up and wouldn't be out of place playing against the Lions. Neither man has started a Test alongside any other second row than Sharpe, though, so, despite being team-mates at domestic level, it would be a major shock if their partnership continued for their country at the expense of Horwill.
Rewind 18 months and both Rob Simmons and Dean Mumm looked to be among the biggest challengers to Horwill's Lions hopes but the pair have failed to kick on in the manner they would have expected. Simmons' suspension on the end-of-year tour of hardly helped his chances of becoming the main man after Sharpe's departure, while Mumm's decision to swap Sydney for Exeter after missing out on the World Cup squad ended his hopes of featuring against Gatland's tourists.
Neville and Pyle performed well enough for the Rebels last term to both be included in Deans' recently-announced 49-man training squad but both remain uncapped and the former only had eight Super Rugby appearances to his name prior to the start of this season.
One player who does offer the experience the Wallabies may well need when the Lions come calling is new Force signing McMeniman. The 29-year-old has just returned from a three-year stint in Japan and has immediately been recalled by his country.
McMeniman made his Wallaby debut as far back as 2005 and signed for the Kubota Spears in 2009 with 21 international caps behind him. He is now hopeful of adding to that tally and has publicly highlighted the looming Lions tour as one of the reasons he was so keen to return home.
Hugh McMeniman is back in the Wallaby fold eight years after his international debut
Outside of the current squad, promising Rebel Luke Jones is still a long way off reaching his full potential and is seemingly caught between being a lock or a blindside flanker but the youngster did keep Neville out of the Rebels' starting lineup against the Force last week.
Veteran Radike Samo offers more versatility in the back five and plenty of experience having faced the Lions with the Brumbies back in 2001 but the 36-year-old will need a huge year to force his way back into Deans' plans.
We could go on and on when it comes to potential Wallaby second rows thanks to the need for new blood to replace Sharpe and Vickerman but we'll keep coming back to the same starting block: prior to injury, Horwill's name was effectively set in stone to face the Lions. And if he doesn't line up against the world's most famous touring team at the Suncorp Stadium, something will have gone horribly wrong for Horwill or horribly right for not just one but two other pretenders.