After activating southpaw Ranger Suarez from the 15-day injured list earlier today, the Phillies are making a change to their rotation mix to get back down to five starters. As manager Rob Thomson told reporters, including Lochlan March of the Philly Inquirer, that means a move to the bullpen for right-hander Taijuan Walker. Thomson did not rule out the possibility of a six-man rotation in the future, but with an day off on Monday the Phillies are planning to use five starters for at least the next couple of weeks.

Walker’s been in the rotation since Opening Day and has pitched quite well in his six starts this year. The 32-year-old has an impressive 2.54 ERA (125 ERA+) in 28 1/3 innings of work, although his peripherals are not quite as impressive. A 17.6% strikeout rate is well below par, and Walker’s 10.4% walk rate is much too high for a pitcher who’s missing bats at a below-average clip. He’s done well to mostly keep the barrel of the ball and induce soft contact so far, but peripherals like his 4.01 FIP and 4.71 SIERA suggest that he’s more of a number five type starter than the mid-rotation results he’s posting so far.

Of course, even being a serviceable back-of-the-rotation piece is a massive improvement over Walker’s performance last year. 2024 was the right-hander’s second season in Philadelphia, and it could have hardly gone worse as he pitched to a brutal 7.10 ERA with a 6.94 FIP in 83 2/3 innings of work spread between 15 starts and four relief outings. Following a season where Walker had more appearances where he allowed at least four runs (seven) than where he allowed two runs or less (six), the right-hander’s position within the Phillies organization was unstable enough that the club opted to trade for Jesus Luzardo and sign Joe Ross in a bid to make Walker less necessary. That left some to suggest he was in danger of being cut ahead of Opening Day entering camp, but the injury to Suarez paved the way for Walker to not only remain on the roster but in the club’s rotation.

Though he’s headed back to the bullpen at this point, Walker’s solid work over the season’s first month was more than enough to solidify his roster spot, and at this point the question regarding Walker is no longer whether he can avoid a disastrous repeat of 2024, but rather if he can continue pitching well enough to force Philadelphia brass into considering a six-man staff at some point this year. Of course, the Phillies wouldn’t necessarily need to consider a six-man rotation in order for Walker to make his way back into the mix, as he’s presumably the next man up to make starts until the Phillies decide to promote Andrew Painter.

The Phillies have generally enjoyed good health in their rotation mix in recent years, but injuries are always a risk when it comes to starting pitchers. There’s no better proof of this concept than veteran right-hander Aaron Nola, who has been one of the most durable and reliable innings-eating arms in the sport for nearly a decade at this point. As noted by Todd Zolecki of MLB.com, however, Nola was experiencing a neck issue prior to today’s game. That led the Phillies to activate Suarez from the injured list today rather than the day of his planned start tomorrow in case they needed a starter to help cover for Nola. Fortunately, Nola wasn’t stopped from pitching by the neck problem and went on to pitch six shutout innings while striking out eight in the club’s 7-2 win over the Diamondbacks this evening. Even so, the last-minute injury scare serves as a reminder that an opening could open in the Philadelphia rotation at any given moment, and it would be a surprise to see Walker passed over for any spot start opportunities as long as he remains effective in his move back to the bullpen.