SAN FRANCISCO -- Willson Contreras, the face of the Cubs' offensive resurgence of late, is likely headed to the disabled list after injuring himself Wednesday while running out an inning-ending groundout. The Cubs lost the game, 3-1, and the series to the Giants.
Contreras will travel with the team to Arizona and undergo an MRI exam on Thursday. The team expects to release the results Friday before the Cubs face the D-backs.
The Cubs will likely recall Victor Caratini trom Triple-A Iowa as a backup catcher. He went 2-for-3 with two doubles on Wednesday.
Contreras -- the newly minted National League Player of the Week -- was moving down the line normally after lining a routine grounder when he pulled up shy of first base, grabbing his right hamstring. He continued to limp down the line, hopping on his left foot before falling down to the grass. He was later helped off the field by team trainers.
"That's no fun," said Cubs manager Joe Maddon. "Having been an expert in pulling hamstrings -- which it appeared to have been -- it's no fun. It's hurts. Everything you do, it grabs. But who knows? Maybe it's not going to be as bad as we think. We'll find out tomorrow."

Anthony Rizzo, who entered the game as a pinch-hitter in the top of the eighth, took over first-base duties in the bottom of the frame.
"It's tough," Rizzo said. "Obviously, he's producing very good for us. He's turned into a horse, and we just have to step up and pick him up."
Rizzo said he talked with his teammate after the game. Rizzo reported that Contreras was in good spirits.
"He said he's had worse than this before," Rizzo said. "Injuries like that -- when you see someone grab like that -- it's not very good. But you never know."
Maddon indicated that an injury to a surging player like Contreras could galvanize the team.
"They know that he's not here right now," Maddon said. "They know how important he's been to us. And now other guys realize, 'Hey. Let's go. We have to pick up the slack that has been created.' I've seen it before."
The injury came at the height of Contreras' surge at the plate. He tallied his third career multi-homer game on Sunday and entered Wednesday with five blasts in his previous six games. Contreras, who normally plays behind the plate, leads all catchers in the Majors will 70 RBIs and a .519 slugging percentage. He's tied for first with 21 homers.

Chicago will rely on catcher Alex Avila, whom the team acquired from the Tigers before the July 31 non-waiver Trade Deadline, with Contreras sidelined. Maddon said he's been impressed with the 30-year-old in a limited sample size.
"I've liked what Alex has done so far, I really have," Maddon said. "Watching him and watching his method, he's actually thrown the ball really well, too. There's a lot to like there."