Graham, not known for his blocking while a member of the Saints, will be in a two-TE set with the Hawks, forcing him to block, by his estimation, "75 percent" of the time.
"Now here I'm blocking quite a bit, and I love it," he said. "It's very important to me to be a part of that here. That's about 75 percent of the offense here. When you have a back like that, you want to be in there on those explosive runs, and you want to be a part of that."
Seisay played in 13 games for the Lions last season and produced five tackles.
The extension is worth a reported $43 million with $22 million guaranteed over four years, according to the NFL.com. Wagner produced 104 tackles and two sacks in 11 games last season.
McDaniel has played in 32 games for the Seahawks over the last two seasons and produced 84 tackles and two sacks.
Wagner -- a key piece in Seattle's dominant defense -- was slated to make just $1 million this upcoming season despite producing over 100 tackles per season three years in a row. He becomes the latest Seahawks player to agree to an extension this week, after quarterback Russell Wilson signed a contract on Friday.
Wagner recorded 104 tackles and two sacks in just 11 games for Seattle last season.