UPDATE (March 9, 2016)
Hearts made it official on Wednesday, announcing that they have signed Kitchen to a deal. Journalist Brian Sciaretta reported on Wednesday that Kitchen's contract with the Edinburgh club is for two-and-a-half years.
Kitchen, who turned 24 on Monday, was drafted by D.C. with the third overall pick in the 2011 SuperDraft. He made 158 regular season appearances with United, starting at least 30 matches in all five of his seasons with the Black-and-Red.
His contract with D.C. expired at the end of the 2015 season, and the two sides were unable to agree to an extension to keep the defensive midfielder in the nation’s capital. Because they made an attempt to re-sign him, D.C. will retain Kitchen's MLS rights.
Kitchen participated in the US national team’s annual January camp earlier this year, coming on as a late-game sub in the USMNT’s 1-0 win against Canada on February 5. He has three career caps with the senior team.
Hearts are currently third in the Scottish Premier League, with the Edinburgh club trailing first-place Celtic by 12 points with 11 games remaining in the 2015-16 season.