He has pencilled in about a third of the players, including his captain
The European quarterfinals could become crucial testing grounds for players still keen to make a final impression on British and Irish Lions coach Warren Gatland.
Gatland, who led London Wasps to both Challenge Cup and European Cup glory before taking over as Wales coach, will clock up the miles this week as he does the rounds of the European matches as he goes in search of the final pieces of his Lions squad jigsaw.
The Lions head coach is due to attend no fewer than five of the eight quarterfinals in the two tournaments and will get the chance to see a number of tour candidates playing in the heat of some very intense battles.
Gatland is due to name his squad of between 35-38 players in London on 30 April and has already stated he has pencilled in about a third of the players, including his captain.
His first port of call will be Kingsholm on Thursday night when Gloucester entertain Biarritz Olympique. Home flyhalf Freddie Burns is bound to come under the spotlight given the injury problems Jonny Sexton is currently experiencing and Gatland will be hoping England No.8 Ben Morgan's ankle injury has healed well enough for him to get back into action.
England midfield star Billy Twelvetrees will also be able to further his claims for inclusion in the party due to open its 10-match tour in Hong Kong against the Barbarians on Saturday, June 1.
Friday night will see Gatland return to his old stamping ground at Adams Park for the second Challenge Cup quarterfinal between London Wasps and Leinster.
Here he will get the chance to see Leinster's all international front row in club action together and the back row duo of Jamie Heaslip and Sean O'Brien take on James Haskell and Billy Vunipola.
The Recreation Ground in Bath will be the third stop of the weekend on Saturday lunchtime, when they tackle Stade Francais Paris in the third Challenge Cup quarterfinal, before he heads back up the M4 to Twickenham to see table-topping Saracens take on Ulster in the European Cup.
That game will throw up a number of fascinating battles with England prop Mako Vunipola packing down against experience All Black John Afoa, Ulster and Ireland hooker Rory Best taking on Springboks Schalk Brits and John Smit, Chris Ashton oppose Andrew Trimble and the two young flyhalves, England's Owen Farrell and Ireland's Paddy Jackson, challenging each other with a place in the semifinals at stake.
Gatland's final port of call will be the Twickenham Stoop on Sunday for the European Cup clash between Harlequins and Munster. This game will finally give him the chance to see the 2009 British and Irish Lions skipper Paul O'Connell in action in his biggest game of the season since his comeback after back surgery.