DUNEDIN, Fla. -- While the Red Sox were rained out against the Blue Jays on Tuesday, there will be a significant development at JetBlue Park on Wednesday when reliever Tyler Thornburg makes his first appearance of Spring Training.

Given the state of flux in the bullpen, the Red Sox are curious about what kind of impact Thornburg can make this season.

The righty spent most of 2018 building his way back from surgery to repair thoracic outlet syndrome in his right shoulder, and his performances were inconsistent after he was activated.

However, Thornburg has been throwing the ball much better this spring. If he can get at least close to what he was when he was with the Brewers in 2016, the Red Sox could have a big weapon to help fill the voids left by Joe Kelly and Craig Kimbrel.

Originally, Red Sox manager Alex Cora was going to travel to Port Charlotte to see the other split squad play against the Rays, but he will instead stay home to watch Thornburg face the Orioles.

Mookie Betts, last season’s American League Most Valuable Player Award winner, will also make his debut this spring in the home game.

Lefty Eduardo Rodriguez, who the Red Sox hope is on the verge of a breakout season, will start against Baltimore. He will become the first pitcher in Boston’s regular starting rotation to make a start this spring. Cora is being conservative with the other four starters (Chris Sale, David Price, Nathan Eovaldi and Rick Porcello) due to their workloads last October.

Other playing plans

Steve Pearce was hoping to play his first game of Spring Training on Wednesday, but that is now in jeopardy after the club sent him home sick on Tuesday morning.

Star slugger J.D. Martinez is projected to play in his first game on Saturday at home against the Orioles.

The Red Sox remain hopeful that second baseman Dustin Pedroia, who played just three games in 2018, can start game action by the middle of next week.