Garciaparra and Ellis came up lame in Tuesday night's 5-4 loss to Texas. Also leaving Tuesday night's game were rookie left-hander Brett Anderson with a blistered finger and reliever Santiago Casilla with a sore ankle.

Manager Bob Geren said Casilla is day-to-day. Anderson's finger could be healed in time for his next start Sunday at Seattle.

Compounding the Athletics' injury problems, first baseman Jason Giambi was out of the starting lineup on Wednesday night because of two sore hamstrings. Geren said Giambi would be available to pinch-hit and could be back to start Thursday's series finale.

Geren was able to get Eric Chavez back in the lineup. A six-time Gold Glove third baseman, Chavez started at first base for the first time since 2001. Chavez had played in only three of the previous 12 games due to a sore right elbow.

Chavez needs a few more days before he'll be able to throw from third base, but he can swing the bat so Geren wanted him back in the lineup. Oakland started the day with a team batting average of .233 and eight homers, fewest in the majors.

Garciaparra and Ellis both sustained their injuries on the basepaths.

Garciaparra was hitting .231 with one homer and nine RBIs in 12 games at third base, first base and DH. Ellis had started 17 of Oakland's first 18 games at second base and was batting .206 with no homers and nine RBIs.

"It was a rough day for us, no doubt," Geren said of Tuesday night's game.

Patterson, obtained from the Chicago Cubs in a trade last July 8, was batting .329 with seven doubles and 16 runs scored in 19 games with Sacramento. Cameron, who signed a minor league contract with Oakland during the offseason after pitching for the San Diego Padres the past two seasons, was 2-1 with a 3.27 ERA in eight relief appearances for Sacramento.

To make room on the 40-man roster for Cameron, the A's transferred right-hander Justin Duchscherer (right elbow surgery) to the 60-day disabled list.