Terry Collins told reporters that he held a team meeting after the Mets lost to the Rockies, 6-1, on Friday.
The Mets, who have lost three in a row, have fallen to 53-49 and 2 1/2 games out of the second Wild Card spot.
They are currently batting a league-worst .202 with runners in scoring position, after going 0-for-8 Friday night. The 1969 Padres are the only team with a lower batting average with runners in scoring position over the course of a full season.
"These players, they're smart guys. They're getting it from their friends, everybody else. 'You guys aren't hitting with runners in scoring position,'" Collins said after the game. "And so, it starts to build and starts to build and all of a sudden they go up there and their heads are not where it needs to be, because they're worried about making an out or not getting a hit."