As far as bullpen X-factors go, look no further than left-hander Mason Fluharty.

It’s already been a remarkable breakout campaign from the 24-year-old rookie, who, despite being optioned back to triple-A on two separate occasions during the regular season, has earned his way up the trust-o-meter within the Toronto Blue Jays’ bullpen and could find himself pitching in crucial situations once the American League division series begins Saturday.

There’s still a chance that Fluharty could be left off the club’s ALDS roster, which must be submitted by 10 a.m. ahead of Saturday’s Game 1 at Rogers Centre. But considering they’re now facing a New York Yankees lineup that features multiple impact left-handed hitters, carrying a second lefty reliever behind Brendon Little would be well-advised.

Chances are, that decision will come in handy while navigating a window that includes Cody Bellinger, Jazz Chisholm Jr., Ben Rice and Trent Grisham.

Given how Fluharty performed down the stretch, retiring 17 consecutive batters — eight via strikeout — over his final four relief appearances, there’s no one better suited for that secondary lefty role, which may include extinguishing fires in the fourth or fifth inning, right now than him.

The responsibility wouldn’t be solely on Little and Fluharty to neutralize New York’s left-handed batters, of course. Toronto’s bullpen also features a pair of righties who’ve enjoyed success in lefty matchups this season — Braydon Fisher (.232 OPP wOBA) and Tommy Nance (.261 OPP wOBA), likely boosting each of their odds of making the team’s ALDS roster.

And if the Blue Jays are to advance to the next round, they’ll also probably need Seranthony Domínguez (.353 OPP wOBA) and Jeff Hoffman (.341 OPP wOBA) to record key outs in right-on-left situations. Those could ultimately prove to be nerve-wrenching, edge-of-your-seat moments, though.

There’s a legit opportunity for Fluharty to put on his best superhero impression here. If he’s on the roster, which, odds are, he will be, there’s a possibility he could be waiting on stand-by anytime a threat is looming with Bellinger’s spot coming up — mainly the second and third time through the Yankees’ order.

But, if that ends up being the matchup, there’s no sugarcoating it — it’ll be a huge test for Fluharty. Bellinger has made a living off enjoying success against both righties and lefties in his career. That was no different this season, as he slashed .353/.415/.601 with a 180 wRC+ in 176 plate appearances versus southpaws.

Of all New York’s left-handed-hitting weapons, he’ll require the most attention from Toronto’s coaching staff. Everyone else is largely boom or bust in left-on-left situations, largely exhibiting a true three-outcome approach (walk, strikeout, home run).

For Fluharty, it’ll all come down to the effectiveness of his low-80s sweeper, which he throws over half the time to left-handed opponents, who hit .174 against it with a 45.8 per-cent whiff rate during the regular season.

But it’s a dependable weapon against right-handed batters, too. Overall, the opposition has gone 2-for-25 (.080) against it since the start of July. That means he’s more than just a lefty specialist at this point. With the three-batter minimum rule in effect, it’d allow the Blue Jays’ staff to deploy him in any situation — even if the Yankees evenly structure their lineup by handedness.

Needless to say, Fluharty has the potential to act as Toronto’s secret bullpen weapon, setting the stage for his breakout party to the rest of the baseball world.