PITTSBURGH -- Their series with the Cardinals has left the Pirates down two catchers.
Pittsburgh will be without Francisco Cervelli for at least a month after he underwent surgery on his left hand at Allegheny General Hospital on Saturday. Cervelli left Friday night's loss to the Cardinals at PNC Park in the fourth inning after injuring the hand during a swing.

The availability of backup Chris Stewart is also in question after he exited after the seventh inning of the Pirates' 5-1 loss on Saturday. Stewart collided with Cardinals outfielder Jeremy Hazelbaker at home plate, aggravating his injured left foot and ankle. Stewart took a foul ball off the ankle two days ago, then fouled another off it on Saturday, though the ball struck a different area.
Though Stewart can usually stomach pain, the pain in his left foot can affect certain catching stances and weight shifts.
"In game mode, I try not to think about it," Stewart said. "I try to just go with what I can. Sometimes, when I run down to first base, I obviously feel it, put a little too much weight on it. I tried to go down after that last one, and I was favoring it a little too much. So they had to take me out at that point."
Stewart is icing, elevating and resting the foot when he can, and keeping it bandaged. He hopes the injury will not affect his playing time.
Cervelli, signed to a three-year contract extension last month, was placed on the 15-day disabled list after undergoing the procedure to excise/remove a fractured hook of the hamate bone. The estimated time of return to full baseball activities is four to six weeks.
With Cervelli down and no Major League-ready catchers waiting in Triple-A -- prospectElias Diaz is still recovering from surgery on his right elbow -- the Pirates acquired journeyman backstop Erik Kratz from the Angels for cash considerations.
Due to Stewart's injury, Kratz got to play sooner than expected, entering in the eighth inning and striking out in his only at-bat.
"You hate to see something like that happen to a player," Andrew McCutchen said of Cervelli's injury. "We've got what we got. We'll be able to pick up the slack. Someone will fill in. We got Kratz. He has some familiarity with the organization. I have familiarity with him as well. It's just something that we've got to overcome and something I'm sure we'll be able to do."
Kratz, 35, began his Major League career with the Pirates in 2010 and has since played for the Phillies, Blue Jays, Royals and Astros. He will likely serve as Pittsburgh's backup, though manager Clint Hurdle said he wasn't sure how they will divide playing time between Kratz and Stewart.
"I think we've got to keep [Stewart] in a competitive place where we can keep his energy strong," Hurdle said prior to Saturday's game. "He's never had to play seven days in a row, six days in a row. So we'll see how it goes. We'll see what's Kratz can bring us as well."
Ankle and foot permitting, Stewart is ready to accept more responsibility in Cervelli's absence.
"This is what I prepare for. ... In the offseason I prepare myself just in case something like this happens and I've got to take over and catch a majority of the time," Stewart said. "Physically, I'm prepared for it. Mentally, I'm always prepared. It's just a matter of going out there and doing the job."
Kratz attended Spring Training with the Padres this year before being traded to the Astros on March 28. He played 15 games with Houston, batting .069 with 14 strikeouts in 30 plate appearances, and was designated for assignment on May 16. Eleven days later he signed with the Angels as a Minor League free agent and reported to Triple-A Salt Lake.
To make room for Kratz on the 40-man roster, the Pirates designated hard-throwing reliever Trey Haley for assignment. Haley, signed to a Major League free-agent deal this offseason, was 1-4 with a 6.66 ERA in 23 appearances for Triple-A Indianapolis this season.
In a separate roster move, the Pirates recalled right-hander Rob Scahill from Triple-A and activated Arquimedes Caminero from his rehab assignment. To make room on the 25-man roster for Kratz and Caminero, lefty Kyle Lobstein and infielder Cole Figueroa were optioned to Triple-A.