Collins is one of four left-handed relievers competing for two open spots in the Nationals' bullpen, Chelsea Janes of The Washington Post reports.
Matt Grace, Enny Romero and Sammy Solis are also in the mix, although the Nats have some roster flexibility to keep more than two of them to begin the regular season with Koda Glover (shoulder) and Joaquin Benoit (forearm) both expected to land on the DL. Collins has the most big-league experience of the bunch, but he also hasn't pitched in the majors since 2014 due to two Tommy John surgeries. He's looked healthy this spring, though, showing his old pop with his fastball and posting a 13:3 K:BB in 8.2 innings. Because he's not on the 40-man roster and can't opt out of his minor-league deal until July 1, the 28-year-old is arguably the longest shot of the four lefties to break camp with the Nats, but a reliever with a proven ability to get tough left-handed sluggers out could be useful in a division with Freddie Freeman, Jay Bruce and Justin Bour around to cause late-game trouble.