Rizzo happy to bring back Sean Burnett

Nats unlikely to retain BurnettThe Nationals’ bullpen may have been their biggest weakness in 2015, but it hasn’t always been that way. In 2012, when they led the majors with 98 wins and won the NL East, it was one of their biggest strengths. They had balance, depth and firepower top to bottom in what amounted to one of the game’s best relief units.

Sean Burnett was a big part of that. A lefty with experience and a deceptive release point, Burnett thrived with the Nationals for four seasons. But in 2012 he was particularly effective, when he held a 2.38 ERA in 70 appearances and pitched well down the stretch of a pennant race. That earned him a two-year free agent contract with the Los…