After all, Bush had never sent a starter back out for the ninth in his entire managerial career that spans six teams and stretches back almost a decade.
But when pitching coach Scott Emerson told Oakland's No. 12 prospect to stay loose, he didn't ask any questions.
The 24-year-old surrendered one run on six hits while striking out six batters over nine innings to lead the Triple-A River Cats to a 6-1 victory over the Fresno Grizzlies on Wednesday.
In doing so, he became the first pitcher in the history of the club to throw back-to-back complete games and the first player to toss a nine-inning complete game in Bush's managerial career.
"Darren Bush just told me that in 10 years of managing he has never let anyone come back out for the ninth, so it's pretty cool," Griffin said. "We had a 13-inning game last night that exhausted the bullpen, so I pitched like I knew I was going to have a chance to go deep into the game.
"[After the eighth] when I got to the dugout, I blew past him, hoping I would not get that handshake. Then my pitching coach came up to me and told me I should go and finish the ballgame. It is awesome when any coach has faith in you. It's good to have that encouragement."
Griffin allowed a first-inning run when Gillaspie's one-out triple was followed by Francisco Peguero's RBI groundout. But from there, Griffin found his groove and retired 15 of the next 17 batters he faced.
In the seventh, Griffin surrendered a leadoff double to Brett Pill and he hit Charlie Culberson with a pitch, but he induced an inning-ending ground ball off the bat of Brock Bond to preserve the 5-1 lead.
"That was huge, man," said the California native. "We had [second baseman] Eric Sogard not feeling well, so Grant Green came in from center field to play shortstop. It's been a while since he's played there, maybe 11 months, but he helped turn it beautifully. That made it so I could keep my pitch count down and go into the ninth.
"To be honest, my defense bailed me out. They made some unbelievable plays on balls and they cut balls off in the gap so that people didn't advance. That had a lot to do with it."
Griffin, who allowed two unearned runs on three hits during a seven-inning complete game in Colorado Springs on Friday, relied on his defense a lot.
Selected by Oakland in the 13th round of the 2010 Draft out of the University of San Diego, the 6-foot-5 right-hander induced 14 ground balls and threw 72 of 93 pitches for strikes.
"About three weeks ago, maybe after my third start, I was throwing a bullpen [session] and the manager pulled me aside and said to throw the ball hard down in the zone and stop trying to nibble at the corners," Griffin said. "He told me to make them hit my fastball and pitch them in to make them uncomfortable.
"Tonight I was throwing my fastball, changeup and cutter, then sometimes my slider and curveball. They were all working pretty well. I went out there and attacked the zone and kept them off balance. I just tried to do the best job that I could; it just worked out that I went nine."
Across two levels this year, Griffin is a combined 5-3 with a 2.64 ERA and 82 strikeouts over 88 2/3 innings.
On Wednesday, left fielder Anthony Recker was 3-for-4 with a two-run homer in the win. Designated hitter Stephen Parker and Wes Timmons also homered in the triumph.
Fresno starter Brian Burres (4-5) allowed five runs on five hits and two walks while striking out four batters over six innings in a losing cause.