The Nationals’ best left-handed relief option all year was 38-year-old Matt Thornton. The 12-year veteran turned 39 late in the season. The 2015 season was one of Thornton’s best, and he’s been very good for the Nationals in the 78 appearances he has made with the team — 1.71 ERA in 52.2 innings. The lefty is now a free agent, and it is not clear whether or not he wants to pitch a few more years, or if the Nationals should commit to a pitcher closer to 40 than 35 who had a 2.18 ERA last year but a 3.52 FIP.
The Nationals should look to get a little bit younger when it comes to their lefty specialist role. Felipe Rivero has great stuff, but is still young and unrefined. A slightly older left-hander like Sipp could prove to be a big asset to the Nationals. The former 45th-round pick has strikeout ability whereas Thornton does not. Sipp is the best free-agent lefty reliever, and should be on the Nationals’ radar. Antonio Bastardo is another left-hander with a decent track record and a familiarity with the National League East.