At 3 p.m. on Monday, Zach Thornton called his father, Paul, to share the news that the New York Mets were promoting him to pitch in Wednesday’s game for his major-league debut.Paul answered the phone from Shirley Ryan AbilityLab in Chicago, where he has spent the past month-plus relearning how to walk after a spinal surgery went wrong.“I’m going,” Zach told his dad.The video chat was brief. Words are hard when emotions are so strong. Quickly, Paul’s eyes welled up with tears.“OK,” Paul said to his son, “so are we.”Paul checked out of the hospital, which means he cannot go back. The rest of his rehab therapy is going to happen in Kansas, where he lives, as an outpatient. That is fine, he said, as long as he can see Zach fulfill his dream of playing in the big leagues. The 24-year-old left-hander will start against Washington on Wednesday at Nationals Park.“It was go and be a dad and support a young man in Zach or take care of my health,” Paul said. “The doctors at Shirley Ryan assured me that my health was in good hands and that they felt as though I could do it. So it really made my decision very easy.”After that memorable video chat, Paul and his wife, Julie, traveled to Chicago O’Hare International Airport to board a flight bound for Washington, D.C. He moved around the airport in a wheelchair. Once they arrive at Nationals Park, they expect to watch their son from Section 114. Paul plans on sitting in a wheelchair seat.