It has been, yes. Multiple times, including before the surgery and after the surgery. Let's go through the timeline: Cardinals visit Los Angeles and agent Scott Boras talks with Ozuna and urges him to see a doctor there in LA, with the blessing of the Cardinals. To that point, Ozuna was not forthcoming about what he was feeling, and he later told me that he would feel his arm go numb after throws and he did not tell the Cardinals this during the first half of the season, preferring to keep playing through the trouble. Boras pointed to a pitch that Ozuna didn't drive in 2018 that he obliterated in 2017 and the player understood that the shoulder was sapping his power, so he saw a doctor. He received a shot and the possibility of future shoulder surgery was discussed. The Cardinals, Boras, and Ozuna all told me that he would revisit LA or a specialist at the end of the season or sometime in late October in order to explore the possibility of a surgery.
After the season, Ozuna was prescribed rest to see how the shoulder responded. At a point later in the winter -- they would reverse engineer that date from being ready for opening day -- he would have a consultation and possibly have that impingement in his shoulder addressed surgically. The idea that he would rest first and then re-evaluate is not unusual because players and teams usually do all they can to avoid surgery -- waiting till the moment it would intrude on the season to make that call.
Consider other examples:
-- Yadier Molina had surgery late in the winter so that he could go with MLB on a tour of All-Stars in Japan and continue on with a family vacation around the world. His surgery was, likewise, set up to get him ready for opening day, not Grapefruit League play.
-- Kolten Wong expected to have surgery on his knee after the end of the season. He was prescribed rest. He was re-checked -- and voila, no surgery. He was encouraged to find that out after bracing himself for the possibility.
These examples are often forgotten when the focus is on Ozuna's timeline. Ozuna did return home to start the offseason. He also did not take the Cardinals invitation to do some of his physical therapy and work at the team's facility in Jupiter. The timing of the surgery wasn't the frustration for the team -- the time spent in Jupiter or with the Cardinals' training staff was. Mozeliak flew down to the DR to see Ozuna in person. He was encouraged, and he urged Ozuna to report to spring training early. Ozuna did. The same day Paul Goldschmidt arrived was also Ozuna's first day on site, and he has been almost every day since working with trainers and coaches on his arm.
Hope that helps.