We are almost one month into the season. We have a little bit more information about major league players than we did at the end of Spring Training, but not much. Player performance at this point in the season is highly dependent on batted ball luck. As a result, we can measure the difference between on-field results and batted ball performance using Statcast’s xwOBA statistic, and judge what to do about the players on our roster.

Here are six players to consider:

Buy: Joey Votto – wOBA: .282 xwOBA: .409

Joey Votto is 34 years old. While he is coming off one of his best offensive performances, fantasy owners are rightfully nervous about his slow start. However, Votto has been one of the league’s worst victims of batted ball luck. Statcast thinks he has been close to the same player as he was last year. If your team is contending and the Votto owner is getting anxious, it’s a good time to make an offer.

Buy: Carlos Santana – wOBA: .270 xwOBA: .426

Per Statcast’s xwOBA estimate, Carlos Santana is the unluckiest hitter in the major leagues. His .151/.301/.288 batting line is not nearly representative of his performance this season. He’s sitting at a 17.2% walk rate–best in his career over a full season–with a solid 15% strikeout rate. The data suggest that Santana is getting great contact as well. Philadelphia is a great ballpark for a power hitter. Carlos Santana is going to hit. You might be able to get him very cheap if you act now.

Hold: Didi Gregorius – wOBA: .461 xwOBA: .410

Before this season, I predicted that Didi Gregorius would be the biggest disappointment on the Yankees roster. Didi overperformed in 2017 with a .293 xwOBA and got very lucky with batted balls. I was very, very, wrong. Gregorius been truly excellent in 2018. His plate discipline is off the charts, with a 9% strikeout rate and 17% walk rate. He’s got 8 home runs already. He gets to bat behind Aaron Judge. Gregorius looks poised to put up a .300/100/100+/30 season. That said, Gregorius has clearly benefitted from batted ball luck. His .461 wOBA is well above his .410 xwOBA. He will regress, but could still be a top-5 shortstop after regression. I’m skeptical that any Gregorius owner could get fair value in a trade right now–owners are likely still skeptical. Hold until the trade deadline.

Hold: Tyson Ross – wOBA: .250 xwOBA: xwOBA: .277

Remember Tyson Ross? The dude was a borderline ace from 2014-2015, pitching just under 200 innings with an ERA around 3.00 and solid strikeout numbers. He was derailed by injuries for two years and was probably on waivers at some point in your league. Some smart owner picked him up as a lottery ticket this offseason. If that owner was you, congratulations! You might have a free SP2/3! Statcast suggests that his 2.81 ERA is deserved. Hold on to Ross for now, since his trade value is probably still pretty limited. However, if your team is as bad as the San Diego Padres, considering trading Ross before the deadline. He could quickly look a lot less elite when the Padres sell him to a contending team in a much worse run environment.

Sell: Brett Gardner – wOBA: .313 xwOBA: .281

Gardner is off to a rough start, hitting .237/.366/.316. His walk rate is still solid, but the power that Gardner showed for much of the last four seasons hasn’t been there. Statcast thinks that even Gardner’s modest batting line is soft–his quality of contact has been very low this season. However, he has been very valuable to his dynasty owner over the last few seasons, including a 20/20 performance in 2017. He still has trade value, but he’s also 34 years old. Unlike Joey Votto, Gardner’s early season performance may be the canary in the coal mine of his decline years. Sell while you can.

Sell: Jakob Junis – wOBA: .230 xwOBA: .341

Jakob Junis has been a bit of a sensation for the Kansas City Royals so far. He’s gone seven innings or more in three of his four starts. His ERA is a beautiful 2.03. He’s just 25 years old with a strong minor league track record. However, Statcast suggests that the performance is a bit of a mirage. His .341 xwOBA implies a below-average performance, close to his 4.54 xFIP. If your team is contending, now is a great time to try and sell Junis. The hype is definitely there, and Junis looks a lot like a pitcher that some rebuilding team might like to acquire. You might be able to get a useful veteran in return. However, his value could take a huge hit from just one bad start, so don’t hesitate.