Cubs manager Craig Counsell said Sunday that Taillon's availability for Opening Day is in jeopardy with the right-hander having shown little improvement in his recovery from a lower back injury since being scratched ahead of Saturday's scheduled Cactus League start against the Rockies, Sahadev Sharma of The Athletic reports.

While Counsell noted that the Cubs aren't yet concerned about Taillon potentially facing a long-term absence, the 32-year-old will be sent in for further testing as the organization looks to get a clearer picture of the injury. Taillon has yet to pitch in a Cactus League game this spring, but he hadn't been shut down from activity prior to being scratched Saturday, as he had been building up in simulated games. However, if Taillon isn't able to quickly move past the back issue within the next week, a stint on the injured list to begin the season would become an increasingly likely outcome. If Taillon is on the shelf at the start of the season, the Cubs could open up a rotation spot for one of Javier Assad, Drew Smyly or Hayden Wesneski.