Halak, 28, has appeared in 40 games with the St. Louis Blues this season recording a 24-9-4 record, with a 2.23 goals against average and a .917 save percentage. He was acquired by the Sabres on Feb. 28 as part of the five-player deal that sent Ryan Miller to the Blues.
He is currently in the final year of a four-year, $15 million contract he signed prior to the 2010-11 season and is slated to become an unrestricted free agent this summer.
Halak was selected in the ninth round (271st overall) of the 2003 NHL Entry Draft by the Montreal Canadiens. He has appeared in 260 career games with the Blues and Canadiens, posting a 139-81-26 record with a 2.38 goals-against average.
The Slovakian has represented his country on numerous occasions including the 2010 Winter Olympics in Vancouver, where he backstopped his team to a quarter-final upset over Sweden en route to a fourth-place finish. He was selected to represent Slovakia at the 2014 Olympic in Sochi, Russia where his team finished 11th.
Klesla, 31, has scored one goal and three assists in 25 games with the Phoenix Coyotes this season. In 659 career games with the Coyotes and Columbus Blue Jackets, the Czech defender has scored 48 goals and 111 assists.
He was traded alongside Chris Brown and a fourth round pick to the Capitals in exchange for Martin Erat and John Mitchell on Mar. 4. He was originally selected fourth overall by the Blue Jackets at the 2000 NHL Entry Draft.
Klesla is in the final year of a three-year deal worth an average annual value of $2.975 million.
Neuvirth, 25, has posted a 4-6-2 record in 13 games with the Capitals this season, alongside a .914 save percentage and a 2.82 goals-against average.
Originally selected in the second round (34th overall) by the Capitals at the 2006 NHL Entry Draft, Neuvirth has appeared in 134 career games with the Capitals, posting a 59-41-13 record along with a 2.67 GAA and a .910 save percentage.
The Czech netminder has one year remaining on a two-year deal he signed with the Capitals prior to the 2014-15 season worth an average annual value of $2.5 million.