St Kilda has extended the contract of American-born ruckman Jason Holmes for another season and upgraded him to the senior list for 2017.

His signature comes on the back of a successful NAB AFL Trade Period for the Saints after they secured midfielders Jack Steele and Koby Stevens, reliable defender Nathan Brown and a pick swap that gives them two first-round selections in 2017.

The pioneering Holmes played the final two games of the season after a consistent year with Sandringham in the VFL to bring his AFL tally to five games, adding to the three he played in 2015.

Holmes, who turns 27 on Friday, became the first born and raised American to play AFL when he made his debut in round 21, 2015.

Recruited as St Kilda's international selection with pick No. 36 at the 2014 Rookie Draft the Illinois-born big man has made outstanding progress after being plucked from America following a college basketball career.

He was elevated to the senior list in round nine this season but his permanent upgrade reflects the esteem in which he is held at the club, battling for a senior spot against a quartet of ruckmen including Tom Hickey, Billy Longer and Lewis Pierce.

St Kilda chief operating officer Ameet Bains said the Saints were pleased to secure Holmes' services for 2017 and praised the Chicago native for his dedication to learning his craft.

"We're thrilled to have Jason commit to the club for another year as we think he's made great strides in his development over his three seasons at the Saints," Bains said.

"Jason is a rapid learner and strong competitor, and is a valuable part of our talented ruck team."