Mother Nature slows down rehab for Cardinals ace

The Cardinals are still waiting for right-hander Sonny Gray to make his regular season debut with the club, after he suffered a right hamstring strain during the spring. His path back to the big leagues got muddied, literally, when this week’s weather prevented his ramp-up from going as planned.

Per John Denton of MLB.com, Gray was going to make a rehab start for Triple-A Memphis at Indianapolis Wednesday but the club changed plans due to the heavy rain in the forecast. Instead, the new plan is for a 50-pitch simulated game Wednesday in Springfield, Missouri, followed by a Triple-A start on April 9, which was around when he was hoping to be back with the big league club. But he’ll now be looking at a return on April 14, assuming a normal four-day rest period after his outing for the Redbirds.

When Gray is ready to return, he should slot into the rotation next to Miles Mikolas, Lance Lynn, Kyle Gibson and Steven Matz in the rotation. That will likely mean that left-hander Zack Thompson gets nudged out. Thompson started Wednesday's game for the Cards and Denton noted that his velocity is way down, more than three ticks below his previous start. Whether that’s indicative of some kind of undiscovered injury remains to be seen.

If he’s healthy, Thompson has an option and can be sent to the minors when Gray gets back. He could also be moved to the bullpen to take over the long relief role currently held by Matthew Liberatore, as Liberatore also has an option and could be sent down for work in the Triple-A rotation.

Gray was signed to a three-year, $75M deal in the offseason after posting a 2.79 earned run average with the Twins last year. He combined a 24.3% strikeout rate with a 7.3% walk rate and 47.3% ground ball rate, finishing second to Gerrit Cole in American League Cy Young voting.

Elsewhere in Cardinal news, right-hander Riley O’Brien was placed on the 15-day injured list on the weekend due to a flexor strain. But earlier this week, Denton relayed that an MRI showed no structural damage.

O’Brien will still require a shutdown period before ramping back up, but that’s clearly a better alternative to requiring surgery and missing extended time. Acquired from the Mariners in November, O’Brien has just 3 1/3 innings of major league experience but had a 2.29 ERA in 55 Triple-A innings last year. His 13.6% walk rate was scary but he also struck out 37.7% of batters faced and got grounders on 57.1% of balls in play.