There are seven relievers scheduled to pitch today. Hendriks is starting and Gibson is the second starter. They will likely each get a couple innings. That leaves 5 innings for the relievers. Perkins, Burton and Duensing will each pitch one inning. Those guys are set to be part of the roster. That leaves 2 innings for the relievers in competition for a spot.
The interesting part of the day for those of us following the bullpen competition starts after that. The guys who pitch first are usually higher in the current pecking order than pitchers who pitch late in the game. That is because the competition earlier is usually better. But there is a wild card in that formula this year with players getting ready for the World Classic. Players on their country's roster need to be in game shape sooner and they will be gone from camp for a stretch. So they may be moved up a bit in the pitching order.
So, with the possible exception of Deolis Guerra who is pitching in the World Classic, the pitchers who get those last two innings today are likely to be a little ahead of the others in the competition. The other guys scheduled today are the three who didn't get a chance to pitch after traveling to Sarasota yesterday, Bryan Augenstein, Anthony Slama, Luis Perdomo. At least one of them should get in the game today.