Ceci, 18, has signed a three-year entry-level contract after being chosen 15th overall in Pittsburgh in June.
An Ottawa native, Ceci is coming off a 2011-12 season in which he scored 17 goals and 60 points in 64 games for the Ontario Hockey League’s 67’s.
In three OHL seasons, the six-foot-two, 206-pound rearguard has 106 points on 30 goals and 76 assists.
Ceci played two games in the recent four-game Canada/Russia Challenge split between Yaroslavl, Russia and Halifax. Following this year’s draft, he participated in his first Senators development camp.
Karlsson, 22, improved immensely with the Senators last season, his third in the NHL, in which he captured Norris Trophy honours as the league’s top defenceman.
The Swede’s 78-point output led all NHL blue-liners and was 25 points ahead of the second-place finisher, Brian Campbell of the Florida Panthers. Drafted 15th overall in 2008, Karlsson collected 45 points in the 2010-11 campaign after a 26-point rookie season in 2009-10.
He also posted a career-best plus-16 rating after being a minus-30 and minus-5 in each of the two previous seasons.