Now Carroll has grabbed the top pass-catching tight end on the free-agent market, with a little help from new assistant coach Tom Cable.
"The Raiders always showed interest," Miller told KHTK-AM in Sacramento, Calif. "Throughout the whole process, I always had good communication with coach (Hue) Jackson, and we talked a lot. Seattle, about a week ago, I wasn't sure if they would be involved in this process. Coach Cable gave me a call, and that's when it started. It's definitely been a crazy last few days here."
Miller is coming off the two finest seasons of his NFL career. Just 25 years old, Miller was a Pro Bowl selection last season after catching 60 passes and five touchdowns, but he was even better in 2009 when he caught 66 passes for 865 yards and three touchdowns.
"That's what people have to realize about him is he's a very complete player," said Cable, now the Seahawks' offensive line coach. "He's going to be able to block off the line of scrimmage ... you can move him around. He can do all the crack blocks. He can do the one-on-one matchups in the passing game."
The deal is worth $34 million, with $17 million guaranteed, according to ESPN.
Miller's arrival could spell the end for John Carlson, who's entering his final year under contract. Carlson played 15 of 16 games last season but caught a career-low 31 passes and had only one touchdown reception during the regular season. Carlson did catch two touchdown passes in the Seahawks' first-round playoff upset of the New Orleans Saints.
Carroll immediately tried to dispel the notion that Miller's signing equaled Carlson's end, saying the versatility and different types of looks the two tight ends could provide were a huge benefit.
"Absolutely. It's exactly what is in our minds," Carroll said. "Anyone that thinks otherwise doesn't get it. We think those guys will play in tandem, on opposite sides, we'll be moving them around to matchups and stuff. I think it's a great asset for us now, and we've always liked to play with two tight ends in a number of different packages, and this just gives us tremendous flexibility at a really high level."
Miller said he's excited to be part of Seattle's new-look offense, which also added quarterback Tarvaris Jackson to go with Rice and Gallery.
"I think it's looking really good with the weapons brought in on offense," Miller told KHTK-AM. "Obviously, Sidney Rice, Tarvaris Jackson, you have Marshawn Lynch running the football and then me working the middle of the field. It's been really good, I'm really looking forward to it. Coach Carroll, I think he develops a great atmosphere. He wins everywhere he goes. I'm really looking forward to getting into football and being a big part of this team."
For his part, Carlson seemed to understand the competitive nature of the situation he was being placed in with Miller's arrival.
"We have to perform on the field," Carlson said. "I have to prove I deserve to be out there, as are the other guys at our position. We're all trying to fight for a spot, for a role. It's like that every year. It's always competitive; you always have to earn your spot."
Earlier Tuesday, the Seahawks agreed to terms with defensive end Jimmy Wilkerson, who adds depth to the defensive line as a potential rusher in passing situations.
Wash said Wilkerson would be used as an inside pass-rusher on third downs, but he also could play at defensive end on first and second downs.
The Seahawks also brought back cornerback Kelly Jennings on Monday and reached a contract agreement with free-agent defensive lineman Ryan Sims.
The Associated Press contributed to this report.