On Opening Day, four of the five American League West teams -- the Astros, Angels, Mariners and Rangers -- saw a reasonable path to the postseason. Other than the Astros, every team also had a significant question or two.
Did the Angels and Rangers have enough starting pitching? Could the Mariners keep their core players on the field and get Felix Hernandez back to pitching at a high level? The Athletics? That's complicated. They were competitive down the stretch last season (31-28), and so it was easy to envision them turning a corner in 2018.
Now that we've got two weeks of the regular season in the books, what's the shape of this race? With four of the five teams off Thursday, it seemed like an appropriate time to identify an X-factor on each of the five teams:

Angels
Shohei Ohtani, starting pitcher/designated hitter
Ohtani is the ultimate X-factor. Beyond the production he brings as both a hitter and a pitcher, there's also the energy he generates in the stands and the dugout. In a long season, it would be a mistake to underestimate the impact this kind of thing can have on a team. Players understand that they are watching history being made, and they are as into it as the rest of us.

Astros
Ken Giles, closer
The Astros are a team with virtually no holes -- except possibly at the back of the bullpen. That's the same issue they had during the postseason, and manager AJ Hinch maneuvered around it brilliantly by using starting pitchers in relief roles. This season, Hinch has enough bullpen depth to get by without having a designated closer, and he might be forced to do that with some of Giles' postseason struggles carrying over into a new season. But Hinch would like to get his closer back in the kind of groove he was in during the 2017 regular season, when Giles made good on 34 of 38 save chances and averaged 11.9 strikeouts per nine innings.

Athletics
Kendall Graveman, starting pitcher
Graveman is 27 years old and has pitched in 79 Major League games the past five seasons. This is the year the Athletics hoped the right-hander would take a step forward in his development. So far, that hasn't happened, as Graveman is winless in three starts with a 9.45 ERA. But the A's remain hopeful, emphasizing that he has the talent to succeed at the highest level. With Sean Manaea and Andrew Triggs pitching well and with James Kaprielian, Logan Shore and others on their way back from injuries, Graveman is truly an X-factor.

Mariners
Dee Gordon, center fielder/leadoff hitter
The Mariners believe Gordon's speed and ability to get on base can transform an average offense into an electrifying unit that can get this team over the hump and back into the playoffs. While there are plenty of other questions, the potential to have this kind of impact player at the top of the lineup adds a dimension that few other teams have. He's averaged 61 stolen bases and 98 runs in his three full big league seasons.

Rangers
Big Sexy, starting/relief pitcher
Bartolo Colon has the potential to do two things the Rangers need badly. First, there's the pitching side of it. This team is desperate for rotation help, and even at 44 years old, he appears to still be able to pitch at a high enough level to help. Second, his contributions to the team's attitude and culture also matter. Young pitchers can learn so much by watching how Colon changes speeds, attacks hitters' weaknesses and keeps his composure in good times and bad. Beyond that, he's good for a few laughs, and that's important for a team that is trying to stay competitive.