Will new reliever rule keep Nats from adding another lefty?

It feels like the Nationals have perpetually been searching for a left-handed reliever who can consistently get left-handed hitters out. Because they have.

Sure, there have been a few guys over the years who have been successful: Mike Gonzalez in 2012, Matt Thornton in 2014, Sean Burnett and Sean Doolittle over multiple years. But there have been far more failures than successes in this department: Enny Romero, Sammy Solís, Tim Collins, Tony Sipp, Matt Grace, Dan Jennings, Tom Gorzelanny, Ian Krol, Zach Duke.

It definitely was a problem this season, so much so that whenever Doolittle wasn't available, Davey Martinez ultimately just decided to use right-handers against lefties and hope for the best.

So it would seem to be a priority again this winter for Mike Rizzo once again to try to find a reliable southpaw for a bullpen that once again needs to be remade. Except a key rule change across Major League Baseball might just convince Rizzo it's no longer necessary.

Though it hasn't officially been approved by the league yet, MLB is expected to require all relievers to face a minimum of three batters per appearance next season. There will be only two exceptions: if a reliever completes an inning before facing three batters or if a reliever gets injured before facing three batters.

We won't know for a while what actual effect this has on the sport, but it sure seems like this is the end of the lefty specialist. Guys who used to be summoned out of the bullpen to record one or two key outs against left-handed batters won't be allowed to be used that way anymore, so clubs are going to have to prioritize the ability to retire batters from both sides of the plate over pure platoon matchups.

"I've been kind of contemplating things in my head, what we want to do and what we want to see and the kind of pitchers we want in our bullpen," Martinez said two weeks ago at the Winter Meetings. "We talked a lot about it. We're still not done finalizing things, but we're going to look at a lot of different options."

As things stand for now, the Nationals do figure to have at least two left-handers in their 2020 bullpen: Doolittle and Roenis Elías. Doolittle, of course, will be pitching in a late-inning role regardless of matchups. Elias ideally would be used in innings where there's at least one or two left-handed batters due up, but he's going to have to prove he can actually get those hitters out.

Elías was effective against lefties early in his career with the Mariners, holding them to a .218 batting average his first two seasons in the majors. In four seasons since, though, they've hit a robust .333 off him, including .368 (21-for-57) this year (most of that coming before his trade from Seattle).

The Nationals hope improved health and some tweaks will help Elías rediscover the form from earlier in his career.

"I think his splits will improve, just because his career splits are much better than his splits were last year," Rizzo said. His stuff's good. We didn't see him pitch much for us, but we've seen him in the past. And prior to the trade deadline, he was closing out games for Seattle. His stuff is good. He's up to 95-96 (mph) with a fastball, and he's got a breaking pitch and a changeup. Again, he never really hit the ground running with us, because of injuries. But we think he'll be a reliable guy for us in the future."

But will the future render relievers like Elías - even if they're successful - unnecessary?