Richy Leon then smacked a single to score Encarnacion for a 2-0 advantage.
The all-stars went three up and three down in their end of the inning.
In the fourth, Rhein hit a double that sent in Levi Funderburk, and Rhein scored off an hit by Encarnacion to put the Bullfrogs up 4-0.
The all-stars then found life as Tony Gonzalez hit a home run to lead off the bottom of the fourth.
Things looked brighter for the all-stars as they held Yuma to three up and three down in the next half inning, but then 'Frogs did the same to the Valley stars.
In the sixth, Yuma proved it was the professional team by racking up five runs.
Alex Sutherland got on base on a double and Funderburk was walked. Diego Rico then hit a single and Jose Montenegro got on first on a fielder's choice in which Sutherland was thrown out at home.
Rhein was then hit with a pitch and Funderbunk crossed the plate.
Encarnacion followed with a grand slam that just slipped inside the foul pole to give Yuma a 9-1 advantage.
In the seventh, Funderbunk drove home Jody Martinez with a single and Encarnacion knocked in Rico on a sacrifice fly. The inning ended with two more Yuma runs that left the score 13-1.
The Imperial Valley team then got on the board again with when Cesar Luna scored.
In the eighth inning, the Imperial Valley team ran out of pitchers and Miguel Baez of the Bullfrogs stepped in to pitch the rest of the game for the all-stars. He struck out Martinez and Nate Dighera to finish the inning.
The game ended on three consecutive strikeouts by teh Stars.
Howard, of Brawley, said it felt good to be back in action in his home area.
"It's been a long time," Howard, 31 and a longtime professional minor leaguer, said. "I had a great time out here."
He said he was reminded of when he played games at Stark Field when he was younger.
"I was in Taiwan and I really couldn't enjoy myself," he explained of his latest pro baseball stop. "I'm rediscovering the love of the game."
Howard said he is optimistic about this season for the Bullfrogs.
"We've got some good players so it should be a good season for us," he said.
The Bullfrogs continue pre-season action this week at Desert Sun Stadium in Yuma.