O'Brien said some of the turnovers are "a complete lack of focus."
"We address it, we emphasize it, we find different ways to drill it," he said. "There's a fine line between overcoaching it, too. We tell them when you're a ballcarrier on our team, you're carrying the hopes and dreams of this football team, and that's what you try to relate to the guys."
"The guys don't mean to fumble, it's just something that happens, and we've got to try to correct it and we've got to stop doing it."
Saturday's first lost fumble, by Bill Belton, set up a field goal. The second one, a botched exchange between center Ty Howle and quarterback Christian Hackenberg, stopped the Lions' last gasp in a 24-10 loss to the Golden Gophers.
Penn State, which needs to win its last three games to match last season's total of eight victories, returns home to Beaver Stadium for a matchup Saturday against Purdue (1-8, 0-5), which has scored just 21 points in its last four games while being shut out twice.
Penn State has three road losses and two overtime victories at home over the last five weeks, but O'Brien said the morale of his players is strong.
"They filed into that team meeting room at 2:40 [Monday] ready to go," he said. "People question what there is to play for. There's a lot to play for - the respect of your opponent, your teammates, the tradition of Penn State football. At Penn State, there will never be a question of what there is to play for."
Nittany notes. O'Brien said that sophomore Ben Kline, who started the last two games at outside linebacker, suffered a torn pectoral muscle on the second play against Minnesota and is out for the season. . . . O'Brien said all-Big Ten wide receiver Allen Robinson was experiencing a "shoulder issue" but should be ready to go Saturday. . . . The coach refused to make his players available for interviews after Saturday's loss. "I just felt like we had a bunch of guys that were not happy with the outcome of that game," he told reporters, "and I felt I wanted to talk to them more than I wanted you to talk to them."