Rios has seen his velocity climb up over the course of the season, The Athletic Philadelphia reports.
Rios' fastball averaged 94.2 mph in April but has risen to 97.1 mph in May, peaking at 99.3 mph. He credits the increase to a change in his delivery that allowed him to generate more power from his legs. The 24-year-old has posted a solid 2.81 ERA through 16 innings this season, though his 21.1 percent strikeout rate and 8.5 percent walk rate are each right around league average. Even with the Phillies' bullpen potentially undergoing a shakeup due to closer Hector Neris' recent struggles, however, Rios would be a very unlikely candidate for future save opportunities, as he's been used in the sixth-highest leverage spots for the Phillies so far this season.