Myers, 21, has one year remaining on the entry-level deal he signed in 2009.
SOG: 122 | +/-: 0
He finished with 10 goals and added 27 assists and 40 penalty minutes this past season and was Buffalo's best all-round defenseman in the seven-game series against Philadelphia in the First round of the Stanley Cup Playoffs.
Myers was selected in the first round, No. 12, by the Sabres in the 2008 Entry Draft.
New York Islanders forward John Tavares has reportedly agreed to a similar long-term extension with his team. It is expected to be announced at an afternoon press conference Thursday.