Wales might need it at the back.
The appointments come against the backdrop of Wales’ failure to reach the World Cup and the beginnings of criticism around the side’s openness.
“He’ll bring some unique skills, particularly when you play Nations League A games when you have to defend a lot,” said FAW chief football officer Dave Adams of Williams’ appointment on the Feast of Football podcast.
“Some of the dark arts of defending, he’ll bring some interesting things for the players to think about.”
There is the thought that Williams would also be prepared to challenge Bellamy’s thinking – seen as healthy part of a management team.
But while Bellamy says he is keen to lean on Williams’ defensive know-how, it will still be the former Liverpool, Manchester City and Newcastle forward’s managerial message.
“With his position, sometimes it’s easier coming from a player who’s been in there,” said Bellamy – a former Wales captain himself.
“Now, I’ll lead a lot on the information, but it’s nice for me to be able to ask ‘What would you see with this? If you played there, how did you feel when I asked you to do that? Is that possible? Is that not possible?’ I believe he’ll be a huge asset to me.”
Sheehan’s appointment also suggested a more defensive focus.
The former Republic of Ireland Under-21 international was seen to have a pragmatic style at Swansea.
But it appears Wales will look to benefit from the 40-year-old’s eye for set-piece work, something he has also been responsible for during previous coaching roles at Luton and Southampton.
“We really want someone who is in tune with restarts and set-pieces,” added Adams.
“In these sorts of games they could be the factor that give us a chance to win the game, because they are going to be very hard games to play in.
“We realise the importance of attacking and defending set-pieces in these next six games, and feel Alan and [goalkeeping coach] Martyn Margetson will bring that level of detail to help the team be best prepared for these games.”