Cardinals’ third baseman Fernando Tatis is out for at least three weeks with a strained groin. Tatis will go on the disabled list before the Cards host Pittsburgh tomorrow. Manager Tony LaRussa says Craig Paquette will see most of the playing time at third base. Paquette filled in well for Mark McGwire when Big Mac missed a week with back trouble earlier this year. Tatis leads the National League in RBI with 28, and is 4th in hitting at .375. The Cardinals lead the NL Central and are off today. Rick Ankiel takes a 3-1 record to the mound against the Pirates tomorrow.