When Ramon Santiago took over for Edgar Renteria at shortstop in the eighth inning last night, it looked like he was coming in as a defensive replacement.  Apparently, I should've been watching more closely.  Renteria appeared to have tweaked his aching hamstring while trying to beat out a double-play ball in the top of the inning and had to come out of the game.  Here's more from Jason Beck:

He left the game after aggravating his left hammy, the same injury that sidelined him before the break.  You could see him struggling to get down the line on that double-play ball in the top of the eighth, even a little bit on that second-inning double.  It wasn't any particular play that tweaked it, he said, but it simply got worse as the game went on.  He hopes to be available tomorrow, but we'll see.  If he's still feeling it after resting for a week, that isn't promising.

Jim Leyland rested Renteria quite a bit in the week leading up to the All-Star break, so it's definitely a concern if he's still hurting there.  But hamstring injuries are often the type of thing that never go away during a season; they just hurt less. 

So it could be an all-reserve left side of the infield tonight in Baltimore, if Carlos Guillen remains back in Detroit to help take care of his wife.