Over the last three basketball seasons, Shaedon Sharpe has played fully in only the second one. He’ll start the upcoming season on the mend, too. On Saturday, the Portland Trail Blazers announced that, according to an MRI, Sharpe had suffered a small posterior labral tear in his left shoulder. He will begin rehab immediately and is expected to sit out the next 4-6 weeks, which would force him to miss at least the beginning of the 2024-25 season. The Blazers open the regular season on Oct. 23 against the Golden State Warriors. Sharpe got off to a terrific start with Portland in 2023-24, but an …