5. Reds RHP Riley O'Brien is squarely on the bubble.
Riley O'Brien seems to have been lost in the shuffle in the Cincinnati Reds search for starting pitching. Even with Luis Castiillo and Mike Minor unlikely to start the season in the rotation, we haven't really heard much positive talk surrounding O'Brien.
The 27-year-old was brought to the Reds organization back in 2020 when Cincinnati shipped left-hander Cody Reed to the Tampa Bay Rays. Since that time, O'Brien has spent the majority of his time in the minor leagues, but did make start last season.
In that start versus the Chicago White Sox, O'Brien lasted just 1.1 innings and surrendered two gopher balls. I can honestly wrap my mind around O'Brien gettng a start or two early this season while Castillo and Minor are ramping up, but the Seattle native has pitched in just one inning this spring.
Perhaps that changes over the next couple of weeks, but for now, Riley O'Brien seems to be on the outside looking in. The Cincinnati Reds could always option O'Brien to Triple-A rather than designate him for assignment. So much will depend on how many non-roster invitees are expected to make the Reds 40-man roster.
There are a few others who could be mildly concerned that they might lose their spot on the Reds 40-man roster. Mark Kolozsvary, Jared Solomon, and Colin Moran come to mind. We'll have to wait and see how things shake out over the next two weeks.