Solis 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 Tim Collins 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. Solis has had a brilliant spring, posting a 14:1 K:BB in nine innings, but he's also the only one of the four lefties with a minor-league option remaining. If the Nats are squeezed for spots on the 25-man roster, that factor alone may cause Solis to begin the year at Triple-A Syracuse, but more likely he will slot into a setup role, where he could be a useful source of holds.