Transition - S4-E15
Visible crew/equipment: When the three victims of the accident are all in treatment 2 with Morton, in the wide shot just as Brackett, Early, Roy, John, and Gil walk in, at the top of the screen we can see the boom mic dipping down into view.
Transition - S4-E15
Visible crew/equipment: When Dixie and Carol stand in the ER hallway, talking about the three accident victims coming in and being swamped, there are two tape marks on the floor near their feet, where Carol and the other nurse were standing just before Dix walked over.
Transition - S4-E15
Visible crew/equipment: At the amusement park, when Johnny, Roy, and Gil climb up to the ride that is stuck, the outlines of the mic transmitters and wires are visible on the backs of Johnny's and Gil's shirts during the rescue.
Transition - S4-E15
Visible crew/equipment: When Roy and Johnny find the two puncture marks, from the snakebite, on the unconscious man's leg, the outlines of the lav mic transmitter and wire are visible on the back, left side of Johnny's shirt. It's also visible on the back of Roy's shirt after he is hit with the cobra venom, and on the back of Gil's shirt when he brings in the defibrillator.
Transition - S4-E15
Visible crew/equipment: After Johnny and Roy arrive at the amusement park where the boy was injured on the go-kart, when the guy who runs the go-kart track walks over to Roy and Johnny, the outline of the mic transmitter is visible on the back of his shirt, and moments later it's also visible on the left side of Johnny's shirt. Also, when the guys scare the second boy with the huge needle, as he runs away the outline of the mic transmitter is visible on the back of the boy's vest.
Transition - S4-E15
Visible crew/equipment: At the start of the episode, when Captain Stanley leans over to hang up the telephone and walks out of his office, the outlines of the lavalier mic transmitter and wire are visible on the back, left side of his shirt.
Answer: I was rewatching a few first season episodes of Charlie's Angels (1976), and in S1xE6 "The Killing Kind," I recognized the same actor. So, to finally fully answer your question, the two baseball players in School Days are played by Rod Perry and Sean Fallon Walsh.
Super Grover ★