Chicago Cubs star pitcher Marcus Stroman will have to wait a little longer to make his much-awaited return to the field.

Medical tests showed that the 32-year-old has a right rib cartilage fracture, and he will continue to be out indefinitely with no timetable for his return to the rotation, as per Patrick Mooney of The Athletic.

The two-time MLB All-Star felt discomfort in his rib after undergoing a bullpen session last Sunday in Toronto following the Cubs' three-game series against the Blue Jays.

"Hopefully, this Stro thing is not crazy serious and he's just pushed back. And if it is, yeah, other guys got to step up," Cubs manager David Ross said.

Neither the team nor the player is sure how or when the rib injury occurred. Ross mentioned that he is likely choosing veteran left-handed pitcher Drew Smyly to fill in for the 2017 Gold Glove recipient, but Hayden Wesneski could also be used.

Stroman was a leading candidate for the National League Cy Young Award, an honor given to each league's best pitchers after the 2017 World Baseball Classic MVP put up solid performances in the early parts of the season.

However, a dip in performance last July, in which he allowed 34 runs in the seven starts and 30 innings, and his current stint on the injured list severely hampers his chances of claiming the accolade.

The 2023 season is technically a contract year for Stroman. He has a choice to opt out of his current three-year, $71 million Cubs contract, which pays him $25 million this year, to negotiate a better deal ahead of next season. On the other hand, he can also opt-in to his 2024 season option, which is worth $21 million.

Marcus Stroman was already dealing with a prior hip strain

Stroman was already on the injured list since the beginning of August after suffering from a right hip inflammation.

The Duke University graduate did not specify when the hip started bothering him, but his performances have seen a considerable decline in July, in contrast to his dominant start during the season.

Stroman had a 9.11 ERA in six starts, with 27 earned runs in 26 2/3 innings since July. He also has thrown only one quality start during that span.

With his hip issue supposedly healed, Stroman was supposed to return to action during the Wednesday game against the Chicago White Sox, the second slate of a two-game series against their South Side counterparts. However, the right rib cartilage fracture emerged.

The Cubs lost yesterday's meeting, 5-3, which saw Ross ejected after engaging in a heated exchange with two umpires.

Named to the MLB All-Star team this season. Stroman has a 3.85 ERA, 1.24 WHIP, and 111 strikeouts in 128.2 innings in 2023.

The Cubs aim to make their first playoff appearance since 2020, and they are slightly lagging out of the playoff picture with a 61-58 win-loss record and 3.5 games behind National League Central leaders Milwaukee Braves, as well as one game behind the final wild-card spot.