This evening sees the first Probables v Possibles game since 2000. While this is enticing fans, the reasons for playing it are far from ideal. For the first time since the Regions were formed, in 2003, no Welsh region has reached the RaboDirect Pro12 play-offs, with the Ospreys, the last to crash and burn. The Welsh management didn’t feel they could have a break of nearly six weeks without some meaningful game time ahead of what promises to be a physically imposing tour of South Africa.

Another polarising issue, and one that highlights the challenges facing Wales’ player retention, is the availability of England-based players. George North is on duty with Northampton tomorrow in front of 80,000 at Twickenham, while the Bath duo of Paul James and Gavin Henson have been prevented from playing due to a Premiership Rugby ruling as the game is being played outside the agreed IRB international window. Throw in Ryan Jones’ ankle injury, yesterday’s hamstring tear to Bradley Davies at training and Owen Williams blotting his hitherto burgeoning reputation with a six-week ban for ‘making contact with the eye area’ of Luther Burrell, and preparation has been far from smooth.

Nevertheless, issues aside, there is an appetite for the game from Welsh public with a sell-out crowd expected at the Liberty Stadium. Here are the key match-ups Warren Gatland will be monitoring this evening.

Fire meets fire: Mike Phillips v Gareth Davies

This sparky duel pitches the combustible Mike Phillips against another feisty West Walian, Gareth Davies. Phillips has had a mixed season, flickering intermittently for Wales in the Six Nations after switching clubs mid-season after another rumoured alcohol-related escapade. Warren Gatland will be watching intently to see whether the 85-cap Racing Metro man still has the desire not only to make South Africa as No 1 scrum-half, but the Rugby World Cup. Gareth Davies was one of Europe’s form players at the end of the season, ending as the Pro 12’s top try scorer. Much smaller physically, Davies is blessed with blistering pace around the breakdown, sharp service and a nose for the tryline. Expect ‘Spiky’ to be bristling to keep the young pretender at bay.

Battle in midfield: Jonathan Davies v Cory Allen

Jonathan Davies is now firmly established among the elite midfielders in Europe. His presence was sorely missed during the Six Nations and he will be a key player in South Africa, ahead of his move to Clermont Auvergne. He will be trading his wares against the rangy Blues midfielder, Allen. The Cardiffian has had something of a breakthrough season at regional and international level, with only a shoulder injury stagnating progress. He possesses decent top-end speed, a rapier 15-metre pass off both hands and handling skills honed on a basketball court. The more experienced Davies, meanwhile may have the edge with his kicking game, game intelligence and robust defence. Who knows, these two could easily end up playing alongside each other for Wales…

Midfield tear-up: Cory Allen and Jonathan Davies will collide this evening

Old friends: Ken Owens v Matthew Rees

Ken Owens has waited patiently for a chance to nail down the No 2 shirt, having lagged behind first, Matthew Rees and then Richard Hibbard, who is recuperating from a shoulder operation. He will be packing down opposite his long-time regional team-mate, Matthew Rees for the first time. Owens has provided Wales with a highly energetic option off the bench in the last 18 months, and he will recognise this is a chance to make a pitch for a regular starting berth. Matthew Rees’ return after five months out recovering from testicular cancer has been nothing short of inspirational, and the renaissance of the Cardiff Blues at the end of the season was credited to his leadership. Both men are likely to tour South Africa.

Leader: Matthew Rees has been welcomed back in all quarters and will face his old colleague Ken Owens

Finally options at No. 8: Taulupe Faletau v Dan Baker

Taulupe has been the model of consistency this season without ever reaching the giddy heights of last year, the caveat that he’s played behind a struggling Dragons front-five. One of Warren Gatland’s most important players, his place has been nailed down since the 2011 World Cup and Wales’ over-reliance on him, has started to be a cause for quiet concern. The emergence of Baker, 22, then, has been seen as a huge positive. A different type of player to Faletau, Baker drives with short powerful steps around the base, in a way reminiscent of Scott Quinnell in his pomp, and he also boasts decent offloading game. It is hoped he will, at least, put pressure on Faletau and provide a different option to the peerless Dragon.

Pretty fly-guy: Toby Faletau has welcomed competition for his place from Dan Baker

Probables v Possibles (Liberty Stadium, KO 7.05pm): 

Probables: Liam Williams; Alex Cuthbert, Jonathan Davies, Jamie Roberts, Jordan Williams; Dan Biggar, Mike Phillips; Gethin Jenkins, Ken Owens, Adam Jones, Alun Wyn Jones (c), Luke Charteris, Josh Turnbull, Aaron Shingler, Taulupe Faletau

Reps: Scott Baldwin, Aaron Jarvis, Samson Lee, Lewis Evans, Josh Navidi, Rhodri Williams, Sam Davies, Dafydd Hewitt

Possibles: Dan Fish; Kristian Phillips, Cory Allen, Steven Shingler, Harry Robinson; James Hook, Gareth Davies; Rob Evans, Matthew Rees (c), Rhodri Jones, Jake Ball, Ian Evans, Andrew Coombs, Ellis Jenkins, Dan Baker

Reps: Kristian Dacey, Owen Evans, Scott Andrews, Macauley Cook, James Davies, Lloyd Williams, Matthew Morgan, Jonathan Spratt