PHOTO (Duke Athletics): Jalen Johnson dunks on a breakaway in the Clemson game. By TOM SHANAHAN The strangest of basketball seasons, thrown off kilter by the COVID-19 pandemic, just got a little stranger. Duke freshman Jalen Johnson announced Monday he’s declaring for the NBA draft. Duke's NCAA Tournament chances were already in jeopardy, but now he's coach's Mike Krzyzewski's latest one-and-done without playing games in February or March. “I appreciate everything about my time at Duke,” said Johnson.…