Every Stanley Cup contender shops for that final piece of the puzzle at the trade deadline.

The Tampa Bay Lightning have done it two years in a row with great success. In 2020, they added Barclay Goodrow to the fold for a first-round pick, solidifying their collection of forwards with a gritty bottom-six depth player. They did it again last year by acquiring defenseman David Savard from the Columbus Blue Jackets to round out their roster with a valuable bottom-pair defenseman.

As we inch closer to the March 21 trade deadline, the B/R NHL writers got together and pondered what deal might be the one that puts a prospective contender over the top.

Tomas Hertl to the Boston Bruins

Whether the San Jose Sharks decide to trade Tomas Hertl or not, one thing is clear: Adding Hertl would be borderline unfair for the Boston Bruins.

The 28-year-old center has been rumored to be on the trading block for months now and will be an unrestricted free agent at the end of the season. With the Sharks falling out of the playoff race in the Western Conference, it makes sense for San Jose to cash in on the Czech star.

Boston is an ideal destination. They already have the most dominant first unit in all of hockey. Among the 228 forward lines that have spent more than 150 minutes together, the unit of Brad Marchand, Patrice Bergeron and Craig Smith have the highest expected goals-for percentage (xGoals%) in the NHL at 71.9 percent. The "Perfection Line," which features David Pastrnak on the right wing instead of Smith, ranks in the top five as well.

Boston also has the most prevalent defensive pairing, at least through the lens of xGoals%, with Matt Grzelcyk and Charlie McAvoy badly outchancing the opposition on a nightly basis to the tune of a staggering 70.3 percent.

What the Bruins have been searching for all season is depth, and boy, oh, boy, would Hertl give them that, especially when you consider the emergence of Jake DeBrusk as a potential top-line threat. But we get the feeling that anyone who skates with Marchand and Bergeron will look pretty good.

With the forward core picking up steam over the last few weeks, slotting Hertl in as the second-line center would give Boston one of the most formidable top-six groups in the Eastern Conference. He'd be skating with Taylor Hall and Pastrnak based on how head coach Bruce Cassidy has been rolling out his lines lately. It's safe to assume that his impact would be massive there.

More than 400 forwards have more than 300 minutes of ice time to their names in 2021-22. Among those players, Hertl's expected goals of 19.7 ranks 33rd, in the same neighborhood as Nathan MacKinnon and Bergeron.

Slot a play-driving finisher like Hertl onto a team that already tends to own the puck, and you've got the perfect trade deadline acquisition for Boston. As an added bonus, Hertl could also help insulate the Bruins against the possibility of losing Bergeron as an undrafted free agent this summer.

The Bruins are projected to have around $13 million in cap space to play with during the offseason, opening the door for a situation similar to the one Hall experienced.