Irish rugby star Tadhg Furlong has been named as one of 11 Irish players to make Warren Gatland's squad for this year's Lions Tour to New Zealand.
"He's got some weaknesses but when I look at it from a Welsh perspective, he's the one player who causes us so many problems when we play England because of his footwork and pace".
Hartley's understudy Jamie George, who spent most of the Six Nations coming on for Hartley around the hour mark, got the nod alongside Ireland captain Rory Best and Ken Owens of Wales.
This year Warburton was replaced as Wales skipper by lock Alun Wyn Jones, who led the Lions in the crucial third Test win against the Wallabies in 2013, and seemed to relish the lack of responsibility when producing five fine Six Nations displays.
It was the havoc caused by Joseph against his Wales teams in the past that persuaded Gatland not to add him to a list of big-name English omissions that include Dylan Hartley, George Ford, Joe Launchbury, Mike Brown and Chris Robshaw.
"I didn't realise the split in the numbers", Gatland said on the issue.
Six Nations champions England have the largest national contingent, with 16 players in an unusually large 41-man squad.
He could even return to action for Cardiff before the Lions depart to New Zealand on May 29, if they reach the European Champions Cup qualification play-offs.
The squad was heavy on power in both the forwards and at center, a sign of the approach the Lions are expected to take under Gatland for what is set to be a grueling tour featuring 10 matches and culminating in a three-tests series.
talkSPORT and talkSPORT 2 will bring you EXCLUSIVE coverage of every Lions match this summer, starting with the clash against the New Zealand Barbarians on June 3. You pick players who can do the job you want them to do, who play the style of game you want them to play.
Hansen said he expects the Lions to play an uncomplicated style typical of what Gatland uses with the Wales team.
The last time the Lions tour New Zealand was in 2005 when Clive Woodward's side lost all three Tests against the All Blacks.
"He's playing pretty good so. he's thereabouts", Hansen told reporters.
"There's been healthy debate about the squad and now that it's been announced we need to get it behind it 100 per cent and get excited about travelling to New Zealand", Gatland said.
'That was when it hit home how big a deal it is and this time against New Zealand is arguably the toughest tour'. "We put together a group of players in each position we felt were in contention and then we went through and individually selected those players". "If Justin Tipuric or Sean O'Brien are playing better than him we make that selection from a coach's point of view".