On the surface, it looked like Bruins general manager Peter Chiarelli’s dealings on trade-deadline day swapped out oranges for oranges on the club’s back end.

In his only two moves, Chiarelli shipped Derek Morris to Phoenix and acquired Dennis Seidenberg from Florida. The GM talked about Seidenberg being a better fit alongside Zdeno Chara on Boston’s No. 1 pair — and in just 17 games in black and gold, Seidenberg proved Chiarelli right.

Seidenberg produced nine points (two goals) in that brief stint with Boston and played with force opposite Chara against other teams’ top lines. Although he left the lineup April 3 with injury, Seidenberg was a key piece of the puzzle in the Bruins’ playoff push.

Of course, the Bruins benefited down the stretch from Seidenberg’s improved play. Now they have to pay for that upgrade, as the unrestricted free agent will be looking to get the security of a multi-year deal (and a comfortable salary) from the Bruins or another club rather than wait around until late summer like he did last year.

Stats: 17 GP, 2-7-9, 6 PIM, plus-6 (with Boston only)

Season highlight: One of Seidenberg’s two goals in black and gold turned out to be a game-winner. And he made a number of key plays on the power play to spark Bostons’ slogging offense. But really the best day of Seidenberg’s season was trade-deadline day, when he was rescued from the disaster of the Florida Panthers and added to a team legitimately in the playoff race to better show off his polished all-around game. It might cost the Bruins a few more pennies now to get Seidenberg signed, but playing a solid two-way game for an eventual playoff team turned out to be a stroke of career luck for Seidenberg.

Season low-light: The Bruins pulled out a 2-1 overtime win at Toronto April 3 despite losing Seidenberg to a wrist injury suffered after a slice from an opponents’ skate in the first period. After the game, the Bruins were told they’d be missing Seidenberg for a week or so. However, when after a couple of days of practice things weren’t improving, Seidenberg got a second opinion — and it was an opinion the Bruins didn’t want to hear. Seidenberg had to undergo surgery, which knocked him out for at least eight weeks and prevented him from getting into the lineup for the playoffs.

Final grade: B-plus
Seidenberg showed few of the growing pains some defensemen have suffered when joining the Bruins on the fly and trying to adapt to head coach Claude Julien’s system. There were a couple hiccups with the puck and a few chances he needed to bury the puck on the power play, but otherwise he was a solid addition.

The crystal ball says … Seidenberg would be nuts not to be go on the open market this summer, where he would undoubtedly get a deal from someone that would set him up nice for the next three or four years. If he re-signs with the Bruins for a cap-friendly amount, Chiarelli would really have scored a coup.