PEORIA, Ariz. -- The Padres more or less finalized their season-opening rotation as they broke camp on Monday, with lefty Kyle Hart and righty Randy Vásquez set to earn the final two spots.

That much became clear when the team made the decision to option righty Stephen Kolek -- the only remaining contender in the race -- to Triple-A El Paso.

With Yu Darvish (right elbow inflammation) slated to begin the season on the injured list, what was once a competition for one spot recently became a competition for two. Righties Matt Waldron (left oblique strain) and Jhony Brito (right elbow soreness) also found themselves out of the mix due to injuries.

That left Hart, Vásquez and Kolek in a tight rotation race that went down to the wire. Kolek made the Padres’ final start of the spring on Monday afternoon against Seattle, working five innings of two-run ball.

After making a smooth transition from the bullpen back into a starting role this spring, Kolek is an obvious candidate for a callup if and when the Padres need a starter. But Hart and Vásquez won the camp battle. They’ll join a rotation that already features Michael King, Dylan Cease and Nick Pivetta at the top -- though not technically in the top three places.

Pivetta had been lining up for the No. 4 spot prior to Darvish’s injury, and in order to remain on schedule he still slots into that fourth game. Pivetta will remain behind to pitch a Minor League game in Peoria on Tuesday, which should line him up to pitch the finale of San Diego’s season-opening four-game series against the Braves this weekend.

That means the Padres’ season-opening rotation will look something like this:

1. King
2. Cease
3. Hart or Vásquez
4. Pivetta
5. Hart or Vásquez

After setting the position-player half of their roster earlier on Monday, the Padres have one decision left to make: the final place in their bullpen. Logan Gillaspie is the presumed favorite there, but choosing Gillaspie means the Padres would leave out Rule 5 pick Juan Nuñez, and thus be forced to return him to the Orioles.

Righty Ron Marinaccio, another contender in that race, was optioned to Triple-A on Monday along with Kolek.