Jake Lamb is expected to step up (in part) following the trade of Paul Goldschmidt. Lamb's education at 1B continued, where he'll be expected to play in tandem with 3B. Lamb struggled last season as his L/R splits remained quite horrendous, but perhaps with a change of approach and more consistent playing time, we could see an improvement. But by the same token, he also needs to adjust to a new position.
According to a recent media session, Zach Greinke claims he's happy in Arizona (with his contract, he should be) and that he feels better this spring training than last. Greinke had an excellent second half of 2018 and was one of the few bright spots in Arizona. That said, his K rate was down and he's a year older (35) potentially playing for a non-contender. I'm still a fan, but his skills are deteriorating.
Among the other Diamondbacks changing positions is Ketel Marte. Marte put together his best offensive season last year, hitting 14 HR with a 104 wRC+. He turns 25 this season, so we could see more in the power department. Marte's value will increase slightly with better position eligibility, but he'll still likely be among the bottom tier of fantasy SS this season, just given how crowded the field is. I would target Marte late in drafts given his age; if he improves in 2019 the same was as last year, you have a definitely fantasy asset.
Yasmany Tomas also spent some time at 1B, who is expected to back up Jake Lamb at first. This could mean a bit more consistent playing time for Tomas, who is trying to justify a spot on the big league roster. Tomas struggled in AAA last season, but did hit 14 HR in 106 games. In 2016, he hit 31 HR in the bigs, but that feels like quite a long time ago. He's worth keeping an eye on to see if he can figure out MLB pitching; he's still just 28.
Per Terry Lovullo, Robbie Ray looked solid during live batting practice this week. In an abbreviated 2018 campaign, Ray displayed excellent strikeout rates, but struggled with command. He'll look to figure that out mechanically this season. Ray is on my target list, because with some fine-tuning, he has the stuff to deliver a top 10 season for starting pitchers. If he can't figure out the control issues, you still have a high K (albeit volatile) pitcher.
