Players who could be X-factors in the 2017 MLB playoffs

Barnes has been a secret weapon for the Dodgers with the ability to play catcher, second and third. He's also been one of the best hitting catchers in baseball, starting or otherwise, with an on-base percentage above .400. Opposing teams will have to account for Barnes coming off the bench.

Betances struggled late in the year, but he's one of the scariest relievers in baseball if he can get back on track. The flamethrower reached 100 strikeouts for the fourth consecutive year and finished the regular season with a sub-3.00 ERA.

While he's not Arizona's closer, Bradley is the team's best reliever. The former top starting prospect finished with a 1.73 ERA this season and is a great weapon as a setup man.

The youngest player in baseball, Devers has been a terrific jolt for the Red Sox at third base. He's shown prodigious power with 10 homers since his late-July call-up.

Diaz is an on-base machine, particularly against left-handed pitching. Likely to come off the bench, Diaz's ability to hit lefties will be very useful late in games.

Forsythe has struggled for much of the year, but he has hit lefties very well. That was a major problem for the Dodgers last season, but the team should be able to at least partially nullify starters like Gio Gonzalez, Jon Lester and Robbie Ray.

Gattis had a disappointing season due to injuries, but he still shows exemplary power. He has a chance to be a key player off the bench for the Astros, particularly against lefties.

Which version of CarGo will the Rockies get? He was terrible at the plate for most of the regular season but has finally woken up in September, hitting above .370 in the month for the Rox. He could carry the team on his back if the hot streak continues.

Harper is just returning from a knee injury that he suffered in mid-August, and it remains to be seen if he had enough time to find rhythm at the plate heading into the playoffs. He could determine how far the Nats advance.

One of the reasons for Minnesota's great late season, Hildenberger has been terrific as a setup man. He's shown nearly perfect control since his promotion.

A pleasant surprise for the Diamondbacks, Iannetta has emerged clearly as the team's best catcher. His offense has resembled what he produced early in his career with Colorado, posting double-digit home runs with an on-base percentage above .350.

Lind has been an incredible weapon off the bench all season for Washington. He hit above .300 with an OPS near .900, his best season since he his Silver Slugger year of 2009 in Toronto.

Acquired at the trade deadline from Oakland, Madson has served as Washington's setup man since the deal. He's having one of his best seasons in 2017 due to near-perfect control and gives the team the ability to shorten games.

McCullers pitched like an ace early in the year, but he wore down during the second half of the season. It remains to be seen what role the Astros will use him during the playoffs, but McCullers does have the ability to be a difference maker if he's healthy.

Montgomery had another great year as a swingman for the Cubs. He should be able to contribute valuable innings during the playoffs and has been able to nullify batters from both sides of the plate.

The oft-injured Morrow made only 36 appearances in the three seasons leading up to 2017, but he's been a gem for the Dodgers. Pitching exclusively in relief, Morrow has shown nearly perfect control and hasn't allowed a home run.

Musgrove opened the year as a starter, but he's taken well to the bullpen later in the year. The control artist has a sub-1.50 ERA and sub-1.00 WHIP during the second half following the switch, also showing the ability to pitch multiple innings.

Neshek has been terrific for Colorado since arriving from Philadelphia at the trade deadline. He allowed only one walk in his first 24 innings with the Rockies and has been an extremely valuable setup man for closer Greg Holland.

A 22-game winning streak takes some surprise contributions, like what the Indians have received from Olson. The lefty has been nearly perfect as a specialist, throwing 19 consecutive scoreless innings. He should have a meaningful role in the playoffs as the team's second go-to lefty behind Andrew Miller.

Elbow issues have moved Price to the bullpen, where he's the highest-priced reliever baseball has ever seen. He has fared well in the bullpen since returning on Sept. 17 and should get a multi-inning role similar to Andrew Miller in the playoffs.

Struggling with arm issues for much of the second half, it remains to be seen how the Indians will use Salazar in the playoffs. He has shown dominance when on the mound this year with nearly 13 strikeouts per nine innings and finished the regular season with 4.2 scoreless innings against the Twins.

Back from elbow issues, Smith threw seven consecutive scoreless appearances late in the year for Boston. He's done enough to win a playoff roster spot and perhaps get the call in key situations. Smith has experience, converting 13 saves with 2.31 ERA for the Mariners in 2015.

Possibly the most disappointing starting pitcher of the 2017 season, Tanaka's struggles continued into September. If the Yankees advance past the Wild Card game, it remains to be seen how they will use their former ace, if at all. If he is able to get back on track, Tanaka could certainly be a difference maker.

The stout Vargas has shown big power again this season, though the holes in his swing are apparent. However, Vargas has helped carry his team at different points of the season, particularly in August, and could help the Twins make a run if he gets hot again.

It was one of Zobrist's worst seasons as he played more of a part-time role at age 36. However, Zobrist has won two World Series in a row and is the defending World Series MVP after posting a .919 OPS against the Indians last year. His experience will be called upon by Joe Maddon again.