Ryan Donato, F: The 22-year-old showed signs of being a top-six forward after signing March 18, two days after Harvard's season ended. Donato will be given a chance to play major minutes 5-on-5 and on the power play. ... Jakob Forsbacka Karlsson, F:After he had 32 points (15 goals, 17 assists) in 58 games for Providence of the American Hockey League in 2017-18, his first professional season, the 21-year-old will be one of three rookies vying for the third-line center job. Selected by Boston in the second round (No. 45) of the 2015 NHL Draft, he played one NHL game in 2016-17. ... Trent Frederic, F: The 20-year-old left the University of Wisconsin after two seasons to begin his pro career and had eight points (five goals, three assists) in 13 games for Providence. The Bruins project Frederic, who they selected in the first round (No. 29) of the 2016 NHL Draft, will be in the mix for third-line center. ... Jack Studnicka, F:Seleced in the second round (No. 53) of the 2017 NHL Draft, he impressed the Bruins in rookie camp and training camp but was returned to Oshawa of the Ontario Hockey League, where he had 72 points (22 goals, 50 assists) in 66 games last season. The 19-year-old, who isn't eligible to play in the AHL, could be the latest teenager to break camp with the Bruins.