Visible crew/equipment: At the start, when Johnny is telling The Stewardess about the underwater rescue and in following shots, the outline of the lavalier mic wire and the dark strap (that holds the transmitter) around Johnny's waist are visible on the back of his shirt, and the mic transmitter is visible on the front, left side of his shirt, above his belt.
Visible crew/equipment: After the airplane rescue, at Rampart when Brackett congratulates Roy and Johnny on a job well done, the outline of the mic transmitter is visible on the front, left side of Roy's shirt, just above his belt.
Continuity mistake: While on the way to the parade in The Old Engine, when Johnny and Roy deal with the fire rescue and reach the roof, Johnny has a rope bundle swung across from his left shoulder to his right hip. However, in the next shot as they run across the roof, the bundle is now swung from his right shoulder to left hip, and the rope is also bundled differently.
Visible crew/equipment: When the doctor shows up at the house of the man who kicked in his TV, as the camera moves back, the top of equipment (presumably the boom mic) is visible and moving in the reflection of the mirror on the wall.
Visible crew/equipment: When Johnny and Roy are working on the man who is unconscious due to electric shock, the bulging outlines of the lavalier mic transmitter and wire are visible on the back left side of Johnny's shirt.
Visible crew/equipment: When Roy and Johnny are at the laundromat with the drunk man, the bulging outline of the mic transmitter is visible on the left side of Johnny's shirt, over his belt.
Continuity mistake: When Roy and Johnny get back to the station, Johnny asks Chet about the condition of the house after the fire, and in the wide shot Johnny has a really red pimple near his chin, but in his closeup the pimple has vanished, only to reappear in the next shot.
Visible crew/equipment: When Charlie, who has smoke inhalation, is placed on the gurney in the treatment room, the actor's white tape mark is visible on the floor, where the nurse stands in a moment.
Continuity mistake: During the house fire, when Chet kicks the door twice he leaves dark marks on the door, but when he kicks the door a third time the marks on the door have vanished.
Camera Bug - S4-E10
Visible crew/equipment: At the accident scene with the truck carrying dynamite, when Roy is leaning over the driver's door, the outline of the mic transmitter is visible on the back, right side of his shirt. Then, when they're carrying the driver to the top, Johnny's becomes visible at his left side.
Camera Bug - S4-E10
Visible crew/equipment: When Johnny is driving Roy nuts by taking closeup pictures of him checking the squad's engine, the outline of the lavalier mic wire is visible on Johnny's back.
Camera Bug - S4-E10
Visible crew/equipment: At the school fire, when Johnny is administering the O2 to the teenager with smoke inhalation, the bulging outlines of the mic transmitter and wire are visible on the back, left side of Johnny's shirt.
Visible crew/equipment: When all the guys are talking to Mr. Gibson, who is stuck in the trench he fell into, the outlines of the lav mic transmitters are visible on the backs of Roy's and Johnny's shirts.
Continuity mistake: When Dr. Morton leaves the room of the patient who attempted suicide to get Jack, he takes the pill bottle from Dr. Early, carries the medical chart holder, and is wearing a stethoscope around his neck, but in the hallway when he gets Jack the pill bottle and chart holder are gone, and the stethoscope is in his pocket. Then, when they walk back into the room, Morton's holding the bottle and chart holder, and the stethoscope is back around his neck.
It's How You Play the Game - S4-E19
Continuity mistake: When Johnny is in the ambulance with the car salesman that was bitten by the tiger, Johnny opens the man's shirt, but does not remove his western tie scarf. However, in the man's closeup the tie is open with the scarf slide removed, and then it's back to being tied with the slide.
It's How You Play the Game - S4-E19
Visible crew/equipment: When Roy and Johnny are on scene at the car accident, the bulging outlines of their mic transmitters and wires are visible on the left sides (above the belts) of their shirts.
Continuity mistake: When Chet and Marco are hosing the gas meter fire, they are both wearing gloves while handling the hoses. However, after Roy helps Chet up from his stumble, there is a closeup of the hoses and it's a bare hand handling the hose.
Peace Pipe - S2-E5
Continuity mistake: After Roy and Johnny find the source of the fuel oil getting into the water supply, when they pull up behind the van, there are three barricades with flashers. The flasher on the sidewalk barricade flips from one side to the opposite side between shots.
Peace Pipe - S2-E5
Continuity mistake: When Johnny and Roy arrive at the apartment with the woman who can't breathe because of her new girdle, she hangs up the phone receiver with the cord across the base. In following shots the receiver is placed properly, and then the other way again.
Continuity mistake: When Roy and Johnny are driving to the parade in the fixed up old engine, they repeatedly switch between the road's right lane and left lane, depending on the camera angle.
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 ★