Jarrod Parker pitched well enough to keep Oakland in the game against Detroit.
Trying to field his position proved costly to the Athletics.
Parker's error allowed the Tigers to score a go-ahead run in the third inning of a 3-1 win over the A's Saturday night in Game 1 of their AL division series.
"If he fields it cleanly, he gets the out," Oakland manager Bob Melvin said.
The right-handed rookie scooped Quintin Berry's dribbler down the first base line with his glove. It looked as if he then attempted to flip it to first baseman Brandon Moss — a converted outfielder — and found out too late his teammate wasn't on the bag.
Berry was safe at first and Omar Infante scored to give Detroit a 2-1 lead in the closely contested opener of the five-game series.
Parker appeared dumbfounded that Moss didn't aggressively charge the grounder or cover first to await a throw.
Game 2 is Sunday, about 15 hours after the final out of Game 1, at Comerica Park before the series shifts to Oakland.
Parker gave up three runs — two earned — and seven hits over 6 1-3 innings. He walked only one, struck out five and gave up a solo homer to Alex Avila that gave the Tigers a two-run lead in the fifth inning.
"It wasn't like we blistered the ball around. Parker was pretty good," Detroit manager Jim Leyland said.
The Tigers chased Parker with two singles in the seventh.
Oakland relief pitcher Pat Neshek entered the game, getting the final two outs of the inning and stranding two runners — soon after the death of his newborn son.
"Not only was it good for us, it was good for him," Melvin said.
Neshek's son, Gehrig John, died 23 hours after his birth and he posted the tragic news on his Twitter account late Wednesday night. He told reporters being at the ballpark and playing catch helped with the healing process.
The A's got off to a fantastic start offensively with Coco Crisp hitting a leadoff homer off Justin Verlander before fizzling at the plate against the reigning AL MVP and Cy Young award winner.
Verlander matched a career playoff-high with 11 strikeouts against the AL West-championship team that led baseball with 1,387 strikeouts during the regular season.
The upstart A's struck out 14 times overall and had only four hits.
"I think we were a little frustrated, yeah," Melvin said.