The concept of 'moneyball' is defined by the recruitment of low cost, undervalued commodities that produce better-than-expected results.

As well as needing to nail prized draft choices, every AFL club's list manager must also be able to uncover the diamonds in the rough that cost very little but may deliver huge bang-for-buck value. A prime example of this is Richmond's 2017 premiership side. While a handful of elite, early draft choices played huge parts in their drought-breaking flag, several bargain-basement trade-ins were also pivotal in their season.

Powerful forward/mid Josh Caddy, a former No. 7 draft choice, was secured from the Cats at a cost of picks 24 and 64 (to acquire Caddy and pick 56). Other additions from rival clubs' lists were also acquired cheaply: trades of picks after 40 were all that were required for Bachar Houli, Jacob Townsend and Toby Nankervis, while the Tigers were able to secure Shaun Grigg in 2010 in a direct swap for Andrew Collins - a player who was not viewed as an ongoing best 22 player. All of these players played crucial parts in Richmond's incredible 2017 premiership win.

But what have been the best moneyball deals in the past five seasons?

In this piece the best five trades and free agent pickups from 2012-2017 will be explored along with two repeatable moneyball moves your club should do more.

Top trades (picks including or before No. 40 were not considered)

Stefan Martin (Melbourne to Brisbane for picks 52 and 71, 2012)

Rationale: Considered too injury prone an unable to lock down a best position at the Demons, Martin has developed into one of the premier ruckmen in the competition. The signs were there in 2011, when Martin secured 364 disposals and 314 hitouts from 21 matches. He also managed 82 disposals from round 14 to 18 in 2012.

But behind 2010 All-Australian ruck Mark Jamar and the developing Max Gawn in the pecking order, Martin was limited to a relieving ruck role and unsuccessful stints up forward and down back. Given this, his output since as Brisbane's lead ruckman should not be a surprise.

Stefan Martin of the Lions battles former teammate Max Gawn of the Demons. Photo by Quinn Rooney/Getty Images

Jarrod Witts (Collingwood to Gold Coast for picks 44 and 62, 2016)

Rationale: Prior to joining Gold Coast, Witts lacked opportunity for Collingwood, only playing two senior games in 2016 as a relieving ruckman behind Brodie Grundy. Witts was putting up AFL numbers while sharing the ruck duties with Grundy in 2015, averaging 10.5 disposals, 22.3 hitouts and 3.7 tackles per game during his 11 senior opportunities but he departed at the end of 2016 seeking greater opportunities.

Since joining Gold Coast, Witts has become one of the club's most consistent players and has developed into one of the better dozen ruckmen in the game. This has occurred because Witts has been given the responsibility to lead a ruck division, an opportunity which would not have arisen at Collingwood.

Paddy Ryder and Jarrod Witts do battle in Shanghai. Sean Garnsworthy/AFL Media/Getty Images

Toby Nankervis (Sydney to Richmond for pick 46, 2016)

Rationale: With Kurt Tippett leading Sydney's ruck division, Callum Sinclair backing him up and with Sam Naismith showing promise, Nankervis was the fourth-string ruckman. Hungry for more opportunity, he was perhaps considered expendable by the Swans.

The signs were there from Nankervis during his second season for Sydney that he could thrive as a lead ruckman. Sharing the ruck duties for seven matches in 2016, Nankervis recorded the highest hitout-to-advantage rating in the AFL and averaged 5.1 tackles per game (third best of all ruckmen). He was also rated inside the top-10 in the competition for centre clearance differential. It can only be said that his move to the Tigers has been a roaring success, with the big Tasmanian playing a lead role in the 2017 premiership.

Toby Nankervis of the Tigers locks horns with Adelaide's Sam Jacobs in the 2017 grand final. Darrian Traynor/AFL Media/Getty Images

Jarryd Lyons (Adelaide to Gold Coast, along with pick 71, for picks 43 and 67, 2016)

Rationale: With Bryce Gibbs requesting a trade to Adelaide (which did not eventuate), Lyons -- despite what was a career best 2016 season -- was pushed out, hoping for a contract offer that Adelaide were not willing to provide him and midfield minutes that would have been reduced.

Lyons in 2016 had the second-highest clearance differential of the top-100 players for attendance and was inside the top 60 in the competition for contested possessions, pressure points and score involvements. Given this, it should come as no surprise that Lyons is playing a more prominent midfield role for Gold Coast and has transformed into arguably the club's most important midfielder.

Luke Hodge (Hawthorn to Brisbane along with pick 44, for pick 43 and pick 75, 2017)

Rationale: With Hawthorn calling time on Hodge's career in brown and gold, Brisbane wisely moved down one position from pick 44 to 43 alongside a late selection to add the four-time premiership Hawk. The exchanging of picks made no difference for Brisbane, with No. 44 used to match Gold Coast's bid of pick 42 on Academy prospect Connor Ballenden.

With Brisbane leaking goals in recent years, Hodge has solidified the club's defence and added veteran experience. In 2017, Stefan Martin was the club's only player over the age of 28 and Brisbane were the youngest team in the competition by more than one year. With the addition of Hodge, Brisbane look more organised on match day, with their young players showing improved growth.

Top free agents

Dylan Roberton (Fremantle to St Kilda - delisted free agent, 2012)

Rationale: Has come into his own since joining St Kilda after requesting a move back to Victoria and has developed into one of the game's most productive general defenders. Spending his first three seasons at Fremantle, Robertson had shown that he could play a role but his production since joining St Kilda has improved greatly in a more rebounding focused role.

Tim Membrey (Sydney to St Kilda - delisted free agent, 2014)

Rationale: Kicking 97 goals from 33 NEAFL games in his two seasons for Sydney (fifth most in the competition), Membrey was unable to break into Sydney's senior team due to the presence of Lance Franklin and Kurt Tippett in the front half. At just 188cm, Membrey was considered too small to be a focal point inside 50m. But he has since thrived at St Kilda (despite this year's yips in front of goal). Possessing the production, capabilities overhead and at ground level, Membrey is an example of if you're good enough, you can make it can work.

Jarrad Waite (Carlton to North Melbourne - unrestricted free agent, 2014)

Rationale: Playing no more than 16 games during any season from 2009-2014, Waite's inconsistency was a drawback. What made him a worthwhile free agent for North Melbourne was his impressive 6.8 marks and 1.9 goals per game during this period. While Waite was 32 before he played his first game for North Melbourne in 2015, and even in his fourth season, he remains a productive and dynamic key forward.

Jarrad Waite has been a massive hit for the Kangaroos. (Photo by Quinn Rooney/Getty Images)

Ricky Henderson (Adelaide to Hawthorn - delisted free agent, 2016)

Rationale: At 28 years of age andunable to secure a best 22 position for Adelaide due to the quality of their other defenders, Henderson was not a required player. While he only played nine games for the Crows in 2016, he played what would be best 22 quality football for any other team, averaging 22.1 disposals and six marks per game while hurting the opposition with his long kicking. This form has unsurprisingly carried over to Hawthorn where he has established himself as a part of their best team. He is a prime example of a club recruiting a player for who he is and slotting him in to fill the role he is best suited to playing.

Mitch Robinson (Carlton to Brisbane - delisted free agent, 2014)

Rationale: Criticised for his occasionally wayward kicking and lack of discipline, Robinson was however capable and productive for Carlton in each of his final five seasons. His contested ball-winning, tackling and aggression were strengths and have carried over to Brisbane where Robinson has received greater midfield opportunity, resulting in a spike to his tackle numbers.

Repeatable Moneyball moves your club should place greater value on

Unwanted veterans: Often delisted or available for a late draft selection, veteran talent is an underutilised method of filling short-term list needs with proven output. The most valuable benefit is the fast-tracking of a club's younger players which can be seen with the successful development of Hawthorn's and Geelong's youth following their 2015 and 2011 premierships respectively, which were won with the oldest best 22 and the most players ever (11) over the age of 29 respectively.

Veterans can also perform roles as on-field coaches, set the example and provide further instruction and encouragement at training.

The key with unwanted veterans is taking the players' age out of the equation. A case in point was Brent Harvey, who was encouraged to retire by North Melbourne in 2016 but overlooked by rival clubs. The AFL/VFL all-time games record holder was the oldest player in the competition in his final year but was the only player to gather at least 496 disposals and kick at least 36 goals in 2016. Playing 22 games or more in each of his final three seasons and still possessing his trademark pace, agility, skills and decision making, Harvey is a prime example of a missed opportunity.

Underutilised rucks: The recruitments of Stefan Martin, Jarrod Witts and Toby Nankervis are prime examples of what to look for in an underutilised ruckman. All three were outside their club's best 22s and despite sharing the ruck duties or playing as secondary ruckmen for their former teams, were producing lead ruck numbers at AFL level. Ruck is the easiest position to identify undervalued talents as clubs typically only play one ruck, which results often in a second capable ruckman getting wasted in the reserves or being forced to play out of position to earn senior opportunities.