Blash's homer cleared two fences beyond the left-field wall and brought McClendon out of the dugout.
"I thought it was going to hit my car, that's why I jumped up," McClendon said. "But it actually went over the car. That was pretty impressive."
Blash, who hit 25 home runs last season between Class A Advanced High Desert and Double-A Jackson, was actually hit by a pitch from right-hander Logan Bawcom earlier in the at-bat but chose to stay at the plate to take his swings.
Romero, who McClendon has said is in the mix for a roster spot, and Franklin, who is battling Brad Miller for the starting shortstop job, each hit two-run homers.
Romero's was to center off left-hander Anthony Fernandez; Franklin's was an opposite-field shot to right off lefty James Gillheeney.
"Romero swung the bat really well," McClendon said. "I was impressed."
The game was a welcome break from the usual camp routine and showed where some of the team is -- perhaps only one or two of those who played Tuesday are expected to make the Opening Day roster.
"The first 10 days have been a grind," McClendon said. "It's nice to have the change of pace. I'm sure the players are happy to have a change of pace as well.
"I saw some good things; I saw some bad things. That's to be expected, and we'll work on it. We'll build on the strengths and work on the weaknesses."
Chris Gabel is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.