SARASOTA, Fla. -- In holding their first full-squad workout on Monday, the Orioles ushered in the first official phase of a spring set to surprise. Fresh faces flood Ed Smith Stadium. Questions litter the roster. Battles abound at nearly every position.
Here are 12 players to watch at the dawn of it all.
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Top prospects
OF Yusniel Diaz
3B Ryan Mountcastle
Orioles camp will be all about the kids, with the next six weeks providing O's brass its first glimpse at the farm system it inherited. Any conversation on that topic begins with Diaz and Mountcastle, ranked as the club's Nos. 1 and 2 prospects by MLB Pipeline.

The prize of the Manny Machado trade, Diaz comes to camp with something to prove after slumping to a .239/.329/.403 line in 38 games at Double-A Bowie last season. Mountcastle, meanwhile, might face some questions on the other side of the ball. The converted shortstop moved to third base fully time in 2018, and could be ticketed for the outfield ultimately. Both are likely to begin the season at Triple-A, but they'll get plenty of looks this spring.
The rehabbers
LHP Richard Bleier
DH Mark Trumbo
The Orioles won't rush Bleier or Trumbo, two of their few veterans guaranteed roster spots if healthy. They have extra incentive for playing it safe, as both profile as potential trade chips down the road, should they return to form.
Eight months removed from lat surgery, Bleier is on a slightly more conservative schedule than the rest of the O's staff, and Trumbo still needs to test his surgically-repaired right knee sprinting before he's fully cleared. But both are on track to be built up enough to participate in Grapefruit League games, with an eye towards being ready by Opening Day. The next few weeks should go a long way toward determining how realistic that goal is.
The Rule 5 guys
SS Richie Martin
INF Drew Jackson
Rare is the club with multiple Rule 5 position players in the same camp (Pitchers are far more common selections, given how much easier they are to stash on a roster, if necessary). The world of three- and four-man benches makes doing so impossible with hitters, which is why nothing is guaranteed for Martin nor Jackson, whom the Orioles acquired in the Rule 5 Draft in December. They'll have to battle each other and a host of others for the open shortstop and utility jobs, then remain on the Major League roster for all of 2019.

If they don't, the Orioles must offer Martin and Jackson back to their former organizations, the A's and Dodgers, for $50,000. So they both stand decent chances of heading north with the club in late March, though the recent addition of Alcides Escobar further complicates the middle infield picture.
The favorite behind the plate
Chance Sisco
Sisco is five years younger than any other backstop in camp, making his path to Opening Day fairly clear. All he has to do is hit.
Of course, Sisco has been here before. A year ago, he parlayed a .429 average in Grapefruit League play into a roster spot, then he hit .181 in the Majors and soon found himself back at Triple-A, where his struggles continued. That made the O's new front office wary enough to spend the offseason loading up on catching depth. Now with Carlos Perez, Austin Wynns, Andrew Susac and Jesús Sucre (once he resolves the visa issues keeping him in Venezuela) in the fold, the O's have plenty of other options should Sisco need more seasoning.
The fifth starter candidates
RHP David Hess
RHP Yefry Ramírez
RHP Luis Ortiz
RHP Jimmy Yacabonis
LHP Josh Rogers
Hess and Ramirez are probably the favorites after combining to make 31 starts in 2018, but this competition could run as many as 8-10 deep. And it may get messy, especially if the Orioles deem Nate Karns more suited for a relief role. Doing so would open up two rotation spots; anyone who falls short qualifies as a candidate for the big league bullpen.
Rogers or John Means may have advantages being the only two left-handed starters on the 40-man roster. Dillon Tate has a chance to pitch himself into the mix. Non-roster invites Sean Gilmartin and Gabriel Ynoa come with big league experience and they are probably worth keeping an eye on as well.