Since the Rays began their current run of four straight trips to the postseason, they rank first in FIP (3.87) and second in ERA (3.74) and fWAR (12.4) by rookie pitchers. Meanwhile, they rank 13th in innings pitched by rookies (1,198) in that same span. Relatively low playing time. High impact. In other words, Tampa Bay knows how to get the most out of its young pitchers.

The next man up: Taj Bradley.

The Rays are calling up MLB Pipeline’s No. 18 overall prospect to make his Major League debut on Wednesday against the Red Sox at Tropicana Field, they announced Tuesday. The move comes after Zach Eflin heads to the 15-day injured list with low back tightness, and the outing is expected to be a spot start as Tampa Bay sought a last-minute replacement in the rotation.

• MLB Pipeline | Top 100 prospects | Prospect video

Bradley last pitched for Triple-A Durham on Thursday and was scheduled to pitch Wednesday for the Bulls, anyway, meaning he heads to St. Petersburg on plenty of rest. After posting a 3.66 ERA and a 1.19 WHIP across 59 frames in the International League last year, he allowed four earned runs on six hits and three walks while striking out eight over seven innings across two starts for the Bulls this spring. Notably, Bradley has yet to throw more than 55 pitches in a regular-season start in 2023.

The 22-year-old right-hander has moved quickly through Tampa Bay's ranks in recent years as his stuff has ticked up, and it’s that exciting repertoire that has landed him in The Show, where he’ll become the first 2001-born pitcher to reach the Major Leagues.

Bradley typically sits in the mid-90s with a fastball that showed more velocity coming out of the missed 2020 pandemic year. In that most recent start at Jacksonville, his four-seamer averaged 95.6 mph and touched as high as 97.5, which it did twice in the fourth inning. Bradley's best secondary pitch is an upper-80s cutter that he uses almost equally to the heater against right-handers. His split changeup also comes in hard -- averaging 90 mph on April 6 -- but has enough separation to be a weapon against lefties, who are hitting just .200 with a .685 OPS against him in the early 2023 sample.

All three of those pitches got three whiffs apiece last Thursday, reinforcing that Bradley has a deep enough arsenal to keep hitters off on any night. He’ll also mix in an occasional upper-70s curveball for show that can give hitters one more option to contemplate in the box.

Listed at 6-foot-2, Bradley has an athletic over-the-top delivery that has long helped him throw strikes at each Minor League stop, and he walked only 6.2 percent of his batters faced at Double-A and Triple-A last season, his lowest mark over a full campaign in the Minors. That should help ease his transition to a Major League bump. The climate-controlled conditions of The Trop will further aid his ability to control the ball (unlike the damp evening during his season debut in Durham on March 31, when he walked three in two frames).

Wednesday’s outing may only be a scheduled spot start for the Rays’ latest rookie, but every Major League start is an audition for more. Entering Bradley's debut with an 11-0 record, Tampa Bay has pushed all the right buttons so far. Calling up its top pitching prospect might be the next one.