The form of rookie ruckman Reilly O'Brien has been very impressive this NAB Challenge and the Crows' lack of height down back could weigh in his favour given his previous defensive experience. However the jump from playing as a defender in the under-18s to the AFL is almost immeasurable. That considered, hard-nosed backman Jake Kelly would be looking for a senior debut in 2015. He finished as runner-up best and fairest in the club's SANFL side last year and his aggression would be to the liking to coach Phil Walsh. He doesn't have the height Adelaide needs, but his ferocious attack on the ball in the back half and his 189cm, 84kg frame would suit the elite level. – Harry Thring

Zac O'Brien played five games when given his chance last season, and the mature-aged midfielder showed he could hold his own at the top level. Against Geelong in the final game of the season, the 23-year-old collected 30 disposals in an outstanding performance. The Lions have a host of young key position players on their rookie list that need time to develop, leaving O'Brien as the logical choice to be elevated should an opportunity arise. - Michael Whiting

Irishman Ciaran Sheehan made a big impression when he broke into the Blues' team late last season. Playing the last four games of 2014 he brought a lot of energy to the Carlton half-back line with his pace and ferocious attack on the ball, and won the Blues' best first-year player award. Carlton has the list space to elevate a nominated rookie before round one and the 24-year-old would appear to lead the race for that spot just ahead of fellow Irishman Ciaran Byrne, Cameron Wood and Blaine Johnson. - Nick Bowen

With 39 senior-listed players, the Magpies have room to elevate third-year rookie Jack Frost onto the senior list. The 23-year-old defender was the only Magpie to play all 22 games last season and has risen through the ranks on the back of his discipline and ability to lock down on his opponents. Forward Corey Gault is also being considered for promotion to replace Brent Macaffer, who is recovering from a torn anterior cruciate ligament, on the long-term injury list. Gault, who debuted in round 23 last season, has shown an ability throughout the NAB Challenge series to clunk marks in packs and finish his work in front of goal. With the Magpies searching for other scoring options to assist Travis Cloke, Gault could be brought in on a needs basis. – Ben Guthrie

After several years on the list, Ariel Steinberg finally made his senior debut last season and even featured in the Bombers' elimination final. He remained on the club's rookie list for another year and appears best placed to be elevated if the club gets a long-term injury. He has become a competitive third tall option in defence and could be used in that role. New recruit Shaun McKernan might also be in line if the Bombers require some more height, although he'll need to step up from his NAB Challenge form. – Callum Twomey 

Shaun McKernan in action for the Bombers during the NAB Challenge. Picture AFL Media

The Dockers currently don't have room to upgrade a rookie, however the Ryan Crowley situation may change that. The man in line to be upgraded would be Tanner Smith. Smith was recruited with pick No.36 in the 2012 NAB AFL Draft. He played one game in 2013 but injuries have plagued him over the last 18 months. The 196cm, 95kg key position player was delisted and then redrafted as a rookie last year. Given the Dockers need for key talls and the likelihood that Luke McPharlin will be managed game to game, Smith appears ready to step in. He has played both NAB Challenge matches this pre-season. – Alex Malcolm

The Cats are electing not to upgrade a rookie ahead of round one, football manager Steve Hocking told "It's not a need at the top of our list at the moment, so we'll wait until we see some exposed form and make some decisions from there." However, of the rookies available – Zac Bates, Cameron Delaney, Padraig Lucey, Michael Luxford, Tom Read and James Toohey – Luxford looks the most likely at this stage. The former elite junior basketballer has added size to his frame and was excellent in a VFL practice match at Simonds Stadium against Collingwood on Saturday. Delaney, who played six games for North Melbourne between 2012-2013, is recovering from toe surgery and is still up to 10 weeks away from a return. – Ben Guthrie

Reliable half-back Greg Broughton was squeezed out at the end of last season as the Suns had to reduce their list by two. However, he is highly regarded by the club, and with two opportunities to upgrade rookies, he is a near certainty. Adam Saad has also made a huge impression in his first pre-season and is a strong chance of being elevated. - Michael Whiting

Greg Broughton hanging tough during the Suns' army training. Picture: AFL Media

The Giants have only one rookie, so Sam Schulz is obviously the contender here. Injuries have limited the 22-year-old in the early part of his career but he was retained on the club's list last year as a rookie and will be the first (and only) player in line if the Giants decide to upgrade a rookie for a long-term injury. Although the club has a few players returning from extended injury layoffs, like Jonathon Patton (knee), Lachie Plowman (elbow) and Liam Sumner (foot), none have been put on the long-term injury list. – Callum Twomey

Opportunities will be few and far between, but 19-year-old Jared Hardisty has impressed over summer and didn't look out of place when he gathered 13 touches against Collingwood in the NAB Challenge opener. The hard-running ex-Claremont midfielder enjoys getting his hands dirty at the bottom of a pack and has tidy skills (he used the ball at 77 per cent efficiency versus the Magpies). The Hawks can't promote a rookie unless a senior player is placed on the long-term injury list, but forward/ruck Sam Grimley or athletic defender Kurt Heatherley would also be in contention depending on requirements. – Travis King

19-year-old Jared Hardisty has impressed the Hawks over the summer. Picture: AFLMedia

Aaron vandenBerg impressed in his NAB Challenge first game with the Demons, coming off the bench as the sub and having an immediate impact. He was unfortunately injured against the Western Bulldogs, which might damage his claims for a spot in round one. VandenBerg is ready for senior football having played in Canberra for the past few seasons, has a big frame and is courageous. What he lacks in class he makes up for in intensity and could be useful as a heavy hitter against the youngish Suns team in the season opener. – Peter Ryan

Aaron vandenBerg in the hands of trainers during the NAB Challenge. Picture: AFL Media

Former Tiger Robin Nahas was unlucky to be delisted from the Roos' senior list at the end of last year. The quick small forward played eight of North's first 13 games in 2014. Before a shoulder injury ended his season in round 14, Nahas had played in six straight games and seemed to have cemented a spot in attack alongside fellow small forward Lindsay Thomas. The 27-year-old's chances of senior selection this season will probably depend on the form of Kayne Turner. Turner was a revelation when he came into North's team late last season and should start 2015 as the Roos' No.2 small forward. But if the youngster's form drops, North has a readymade replacement in Nahas. - Nick Bowen

It was a courageous move by Nathan Krakouer to return to Alberton considering the way he walked out on the club to join Gold Coast in 2010. His dedication to training in 2014 and this year has been a credit to him, though, and solid form in two NAB Challenge games have confirmed he still has what it takes. The Power will look to use his foot skills out of defence this year – although he still has a way to go before he's ready for regular senior football. He's very clever in attack as well and at 181cm he's extremely quick off the mark.  Harry Thring

The Tigers can nominate one rookie before the start of the season to play AFL games, and Kane Lambert is at the front of the queue. A star in the VFL, he has shown through the NAB Challenge he can be a ball-winner against AFL opposition, winning eight possessions in the first quarter against the Western Bulldogs. Anthony Miles was a rookie revelation last year and he has backed Lambert to take the same path in 2015. If successful in emulating Miles, the 22-year-old, who was recruited from Williamstown, will add the depth so far missing in Richmond's engine room. – Nathan Schmook      

Ball-winner Kane Lambert
celebrates a goal during the NAB Challenge.Picture: AFL Media

After serving an 18-month ban for taking a banned substance, Ahmed Saad has grabbed his second chance on the Saints' rookie list. The club has noted his dedication since returning to the club after a period training on his own, and he has impressed since re-joining his teammates in January. There is room for Saad to be elevated ahead of round one with Daniel Markworth (shoulder) and Arryn Siposs (shoulder) both sidelined for long periods. He has kicked one goal in each of the club's two NAB Challenge games, but it is the 25-year-old's defensive pressure that could convince the match committee to recall him for his first game since round 19, 2013. – Nathan Schmook 

The Swans have 38 players on their primary list so have two spots open and up for grabs. The club's list of six rookies has plenty of youth, and tall defender Lewis Melican has already had a taste of NAB Challenge action. In fact, they have a few bases covered with their rookies, with mature-aged half-back Nic Newman also a chance to play some senior footy this year once he overcomes a knee injury. Unfortunately Lloyd Perris' run of knee injuries has continued and the midfielder appears a little way from being match ready, but if a ruckman is required, Sam Naismith may be called upon. - Callum Twomey

The retirement of Beau Waters and the injury to Eric Mackenzie gives the Eagles flexibility to upgrade a rookie. Irishman Paddy Brophy and youngster Rowen Powell are the two defenders on the rookie list but it's unlikely either will be upgraded. Murray Newman and Kane Lucas would be more likely options despite both being midfielders/forwards. Newman looked sharp in his outing for East Perth last Friday night and the Eagles believe he is capable of returning to AFL football this year. Lucas is a ready-made AFL midfielder who has played in all of the pre-season matches so far and has been recruited specifically to step up if an injury occurred. Lucas would appear most likely but Newman is an exciting prospect. – Alex Malcolm

Former Hawk Jordan Kelly failed to play a senior game in his three seasons at Waverley Park, but he must have done something to impress Luke Beveridge, who was his backline coach at Hawthorn over previous two seasons. The medium defender possesses a hard body and at 192cm, has the ability to play tall or small. The Dogs have the capacity to upgrade Kelly to the senior list if they place Tom Liberatore, who will miss the season after tearing his ACL, on the long-term injury list. - Ryan Davidson