TAMPA, Fla. — The Phillies might have to begin the season without one of their highest-paid pitchers. Right-handed reliever Tommy Hunter is sidelined with a strained flexor muscle in his pitching arm, manager Gabe Kapler said Tuesday.

Hunter, who began last season on the disabled list with a strained hamstring, will not throw for two weeks before he is re-evaluated. The Phillies are counting on Hunter to play a key role in their bullpen, which they chose to bolster this offseason instead of adding to their starting rotation. The 32-year-old is in the last season of a two-year, $18 million contract.

Hunter missed the first three weeks of last season but still pitched in more than 60 games for the second straight year. He posted a 3.80 ERA with 51 strikeouts and 15 walks in 64 innings.

Monitoring starters

Aaron Nola’s first start of spring training last season came on Feb. 25, four weeks before he would throw the first pitch of the Phillies’ regular season. Nola, shouldering the usual workload of a starting pitcher during Grapefruit League play, pitched the first two innings of a nondescript game that afternoon. This was the way pitchers prepared for the season.

But the Phillies are changing course this spring. They plan to use minor-league starters for their first 10 games before turning to Zach Eflin on March 2. Nola’s first start will be on March 6, three weeks before he starts on opening day. The Phillies, Kapler said, are instead having their major-league pitchers pitch against their own hitters on the backfields of the team’s complex in “intense, live batting-practice sessions.”

“One of the things we’ve seen in past spring trainings is starters running higher pitch counts, and needing to come out of major-league spring-training games without getting their necessary workload to effectively build them up,” Kapler said. “By letting them build volume in these live BPs, we can safely control the environment. We feel that a consistent ramp-up period will lead to the best outcomes for our guys both from a strength and a health perspective.”

Extra bases

The Phillies’ scheduled game in Tampa against the Yankees on Tuesday was rained out and won’t be rescheduled. … Cole Irvin will start Wednesday for the Phillies at Spectrum Field against the Twins.