WILMINGTON — Bruins coach Claude Julien  either does not want anybody to know exactly what his plans are with returning center Marc Savard  or he just does not know what to do with Vladimir Sobotka. On Thursday Julien switched up his white-sweater line from what he had on Tuesday, flipping wing Daniel Paille  from the fourth line in a red sweater to riding shotgun in white with Savard and Michael Ryder .
Sobotka, who, it appeared, had been forced from his center position on the third line to the wing with Savard, was bumped down to the fourth line where he presumably would play center as Steve Begin gets bumped to the wing with Blake Wheeler  (in red for second day in a row) and Shawn Thornton  gets bumped down to the fifth line with Brad Marchand  and Trent Whitfield. Wheeler skated with Sobotka on a penalty-killing unit for multiple drills at Ristuccia.
The Bruins added a defenseman from their pool of Black Aces to bring them to nine total as Andy Wozniewski joined the team at the practice facility. That gives the Bruins three Providence blueliners, with Jeffrey Penner and Andrew Bodnarchuk still with the team after being call-ups late in the regular season.
The Bruins also announced on Thursday that they have signed defenseman Matt Bartkowski to an entry-level contract. The 21-year-old skated in 39 games for Ohio State this past season, registering six goals and 12 assists. The 2008 seventh-round draft pick (190th overall) was acquired by the Bruins at the trade deadline along with Dennis Seidenberg  from the Florida Panthers .