The Washington Capitals acquired the top rental asset on the open market Monday night, landing talented puck-moving defenseman Kevin Shattenkirk in a seismic trade with the St. Louis Blues, the teams have confirmed.

In exchange, the Blues acquired Washington's first-round pick this summer, a complex conditional selection in the 2019 NHL Draft, along with forwards Zach Sanford and Brad Malone.

Washington will also re-acquire 25-year-old goaltender Phoenix Copley as part of the agreement.

St. Louis reportedly retained 39 percent of Shattenkirk's $4.25-million salary to complete the transaction, according to TSN's Darren Dreger.

The Capitals are already, in many ways, the NHL's most complete team, and their current configuration on defense has been the league's stingiest unit this season. But with the mobile Shattenkirk, they have added a completely new dimension to their back line.

The 28-year-old is one of the league's premier transition facilitators, and a power-play specialist. He owns the fourth-highest points rate among blue-liners in all situations, meaning just three of his peers have been more productive with their minutes this season.

Shattenkirk is in the final year of his incredibly team-friendly deal. He stands to fetch a lucrative long-term agreement as the most sought after free agent this summer.

The acquisition made two days before the March 1 deadline also prevents the Pittsburgh Penguins and New York Rangers - two Metropolitan Division heavyweights with similar aspirations and apparent interest in Shattenkirk - from bolstering their respective lineups with the ice-tiling rearguard.

Copley's inclusion in the deal acts as protection for the Capitals should backup Philipp Grubauer be chosen in the expansion draft.