PHOENIX -- Second baseman Freddy Sanchez had to leave Monday night's game against Arizona in the bottom of the first inning with a twisted left knee.
Sanchez will undergo an MRI on Tuesday, but manager Bruce Bochy already wasn't counting on being able to have him available for Tuesday night's game against the D-backs.
"He's day-to-day for now, but I assume he's definitely out [Tuesday]," Bochy said following Monday's 5-4 victory in the opener of the series against the D-backs.
The aggravation of the injury that had marred Sanchez around the time of his late-July acquisition from the Pirates occurred in bizarre fashion: as he gloved an innocuous throw in from center fielder Aaron Rowand after Justin Upton had flied out.
"The throw was a little bit off," Bochy said, "and as he adjusted to get it, his spikes caught in the dirt and he twisted the knee."
Shortly after Mark Reynolds had given the D-backs a 2-1 lead with a two-run homer off Barry Zito with two outs, athletic trainer Mark Gruesbeck and Bochy emerged to check on Sanchez, limping around on the field.
It was a brief visit. Sanchez limped off the field, leaning on Gruesbeck's right shoulder for support.
Kevin Frandsen replaced Sanchez at second base and in the two-hole in the lineup.
It came minutes after Sanchez had given the National League Wild Card-contending Giants a 1-0 lead in the top of the first, beating out a grounder to short for an infield single and working his way around to eventually score an unearned run when Pablo Sandoval's grounder went through D-backs second baseman Ryan Roberts for an error.
Acquired in a July 29 trade from the Pittsburgh Pirates, Sanchez was playing his 25th game with the Giants, the first-inning single raising his average to .284 in 102 at-bats. He missed three games before his trade to the Giants and the three games following the deal with an inflamed left knee, and he also spent two weeks on the disabled list with a strained left shoulder, being activated on Sept. 7.
Tom Singer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.