"I think players are understanding of what goes on around them," said Red Sox manager John Farrell. "I think they are fairly aware. In Sandy's case, where he's out of options. And at that position, you're always a foul tip away from needing another guy. From the performance of Sandy with the combination of organizational depth, we felt like this was the move we needed to make."
Leon's defense has always been a strength, but his offense has come out of nowhere. The switch-hitter is hitting .500 with eight doubles, a homer and nine RBIs in 40 at-bats.
"I just feel good right now," said Leon. "I'm just seeing the ball really well. I'm not trying to do much more, just keep it simple, just try to go up there and put good swings and put the ball in play."
By comparison, Vazquez was hitting .226 with a homer and 12 RBIs in 164 at-bats in his comeback from Tommy John surgery.
Hanigan, who gives the Red Sox a sound veteran presence behind the plate and with his bat, has been out since June 5 with a neck strain.
Meanwhile, Leon will just try to keep the best offensive stretch of his career going for as long as he can.
"He's been unbelievable," said Red Sox left fielder Brock Holt. "We laugh every time he gets a hit now. We should be laughing every time he gets out because he hasn't gotten out very much. He's been great for us and a huge part of what we've been doing."
Entering the season, Leon had a career average of .187 in 209 at-bats.
"When you work hard, something is going to happen at some point," said Leon. "I've been working hard all my career in the Minor Leagues and in the big leagues and in Venezuela. Just play the game and let it happen and things will work out."
Ian Browne has covered the Red Sox for MLB.com since 2002. Follow him on Twitter @IanMBrowne and Facebook. This story was not subject to the approval of Major League Baseball or its clubs.