ST. PETERSBURG, Fla. -- The surging Tampa Bay Rays placed starter Zach Eflin on the 15-day injured list with lower back tightness, manager Kevin Cash said Tuesday.

Speaking prior to the Rays' game against the Boston Red Sox, Cash told reporters that prospect Taj Bradley will be promoted from the minor leagues and start in Wednesday's series finale vs. Boston.

The Eflin move will be backdated to April 8, so the right-handed veteran will miss at least two turns in the rotation, including Wednesday's game for the Rays, who have won 10 straight games to open the season. That said, Cash said that his IL stint should be minimal.

Eflin, 29, a free agent acquisition from the Philadelphia Phillies, is 2-0 in his first two appearances for first-place Tampa Bay. He has 12 strikeouts and a 3.27 ERA in 11 innings of work.

The Orlando, Florida, native told the Tampa Bay Times that he's had lower back issues in the past and that he's not very concerned about this time around despite the fact that Tampa Bay ordered an MRI just in case.

Eflin, who signed a $40 million, three-year contract with the Rays, began last season in Philadelphia's rotation but his last start was June 25 before being sidelined by right knee soreness. He returned Sept. 14 and made seven appearances out of the bullpen with a 1.17 ERA, then pitched in relief in 10 postseason games for the National League champions. He threw 4⅓ scoreless innings over four World Series games.

His 2021 season was cut short by a torn patellar tendon in his right knee that required surgery. He had surgery on both knees in 2016, the same year he made his big league debut with the Phillies.

The Associated Press contributed to this report.