The 25-year-old Goligoski, a Stanley Cup champion with Pittsburgh in 2009, is an offensive-minded defenseman. He has 31 points (nine goals, 22 assists) and a plus-20 rating in 60 games with Pittsburgh this season. He had 37 points (eight goals, 29 assists) in 69 games with the Penguins last season.
Goligoski is in the second year of a three-year, $5.5 million contract. He makes $1.5 million this season and he'll make $2.75 million next season. His cap hit is $1.833 million.
"Anytime you do a trade you are trying to make your hockey club better," Stars general manager Joe Nieuwendyk said. "I think when you add a guy like Alex Goligoski, it really improves your defense. He's a two-way defenseman that is really going to help getting the puck to our forwards. He is a smart player. I think that's been a big need for us."
For the Penguins, Goligoski proved expendable, given the Penguins' depth at defense. It's a group that's led by Kris Letang and rounded out by the offseason free-agent acquisitions of Paul Martin and Zbynek Michalek.
Neal, 23, was Dallas' second-round selection (33rd overall) in the 2005 NHL draft. He appeared in 59 games for the Stars this season, scoring 21 goals and 18 assists for 39 points.
Niskanen, 24, has appeared in 45 games for Dallas this season, recording six assists with 30 penalty minutes, a considerable drop from 2008-09, when he led all Stars defensemen with 35 points (six goals, 29 assists). He was Dallas' first-round pick (28th overall) in the 2005 draft.
"The injuries had not had a lot to do with what I've been looking at. This is for now, plus down the line for both of these players. So that's encouraging," Penguins general manager Ray Shero said during a conference call. "There's not many of these power guys in the game. And Neal, on our list is one of the better ones in the game and has got some room to grow. That's why when you can get a guy like Neal, the opportunity might not be there again."
The parameters of the trade were agreed to Sunday night, and both sides completed it hours before the Penguins played host to the Washington Capitals.
Neal will help the Penguins in the short-term as well. Pittsburgh entered the game down 10 regulars, including captain Sidney Crosby, who is out indefinitely with a concussion, and Evgeni Malkin, who will miss the rest of the year after having surgery to repair torn knee ligaments.
Overall, the Penguins are without players who have combined to score 86 of their 174 goals this season.
Add Martin to the list, who is day to day. He was shaken up after being checked into the boards during a 3-2 shootout loss Sunday at Chicago.
Neal and Niskanen were scheduled to arrive in Pittsburgh later Monday, and be ready to practice Tuesday. They're expected to play Wednesday, when Pittsburgh plays host to San Jose.
The Stars host the New Jersey Devils Tuesday.
Mark Stepneski covers the Stars for ESPNDallas.com. Information from The Associated Press was used in this report.