While Young Sheldon season 7 will need to update viewers on the lives of the Cooper family, The Big Bang Theory spinoff's next outing also needs to bring back a forgotten supporting star. The cast of Young Sheldon is pretty sizable and this often results in supporting characters falling by the wayside. Unless Sheldon's subplot involves his workplace, it is not uncommon for episodes of Young Sheldon to leave out Dr. Linkletter and Dr. Sturgis or only feature Sheldon's colleagues in brief cameos. However, some dropped supporting characters are a little more notable and consequential.
For example, when Young Sheldon's Mary/Brenda fight ended, Brenda began to play a much smaller role in subsequent episodes of the spinoff. Until the confrontation between Brenda and Mary in Young Sheldon season 6, episode 17, "A German Folk Song and an Actual Adult," it seemed as if the series could be setting up George's affair with Brenda. However, this turned out to be a misdirection. Here, Brenda's reduced role effectively acted as evidence that George Sr and Mary were getting on well again and fears of infidelity no longer plagued their marriage (for now).
Similarly, even though Pastor Rob was mentioned by Mary, George, and Brenda in "A German Folk Song and an Actual Adult," he has not appeared onscreen in some time. Pastor Rob played a major role in Young Sheldon season 6, episode 8, "College Dropouts and the Medford Miracle" but, since then, his role in the spinoff has been minimal. Notably, it was Young Sheldon's villainous Pastor Jeff who gave Sheldon the money to go to Germany near the end of season 6, and it was Jeff who brokered a truce with Meemaw in the season finale, rather than Pastor Rob.
As such, the status of Pastor Rob and Mary's relationship remains unclear. When Mary confronted Brenda about her closeness with George Sr, Brenda compared her relationship with Mary's husband to Mary's relationship with Pastor Rob. While this successfully silenced Mary, it is not clear what that relationship now consists of since Mary was excommunicated from the church. Ever since the news that Georgie got Mandy pregnant reached their small hometown, Mary was unwelcome in the church. As a result, Pastor Rob's absence makes it unclear how he is communicating with Mary (assuming that the pair are still in touch).
While Young Sheldon season 7 must explain Georgie's story and Sheldon's return from Germany first, the spinoff still needs to answer for Pastor Rob's absence. Young Sheldon season 7 must bring back Pastor Rob both to explain where he has been and to clarify what his relationship with Mary is like now that she has been out of the church for some time. While it would make sense for the spinoff to reveal that Pastor Rob moved on from the family's small town, this would rob viewers of closure. After all, Mary and Pastor Rob's Young Sheldon connection has been a cause of contention in The Big Bang Theory's spinoff.