Carl completed the formalities of a medical on Tuesday morning and Alan reveals that he has been a target for the club for some time.
"Carl is a player we have been tracking for eight or nine months and he is well known to me and of course Peter Grant, who coached him at Bournemouth.
"He can play two roles, in midfield or as a defender, and he is a very good passer and user of the ball.
"But most importantly of all he is a leader and a character - and we need a few more of those.
"I think he will be important to us this year and he will be looking to make an instant impact into the team.
"He is a Welsh international and we have got what we feel is a fantastic deal for him.
"We know that he is good enough to play in our team and after the result last night this provides the competition we want.
"He is very comfortable in possession and, after his character, that was the thing I was looking for.
"Without Michael Carrick we do lack someone that can pass a ball well - and he can do that, whether he is in defence or midfield.
"He is only a young international, having just broken into the Welsh team - and he is in good company there, because that is a proper team."
Alan is still looking to bring in a new face or two, and he explains:
"It is top of my list now at this club to have players who have the character to get this team out of the division.
"I will certainly have one before the next game kicks off and maybe two more."
Carl made over 220 league and cup appearances for the Cherries after progressing through the youth ranks under now first team boss Sean O'Driscoll.
The Poole-raised youngster was handed the captain's armband following Eddie Howe's departure to Portsmouth in March 2002, and carved his name in Cherries history when he netted twice in the 5-2 Division Three playoff Final win over Lincoln in Cardiff in May 2003.
Despite spending most of the past two campaigns playing at centre-back, Fletcher has switched to his more familiar midfield role this season and won his first international cap in Wales' 4-0 friendly rout of Scotland in February.
Fletcher made his Cherries debut as a 17-year-old second year trainee at Grimsby in February 1998, going on to score 23 career goals at Dean Court.