Wilson injured his leg running the bases against the Atlanta Braves in the third game of the season. He was placed on the disabled list April 6 and, since that time, setbacks have limited his defensive workouts at extended spring training in Bradenton, Fla., and canceled a planned rehabilitation stint at Double-A Altoona.
As a result, the Pirates are taking a more cautious approach with the former All-Star.
"I'm not going to say (when Wilson will return)," Pirates manager John Russell said before Pittsburgh's game against Atlanta on Sunday was postponed because of rain. "Right now, it's when Jack's healthy, Jack will be back. We tried to put some sort of timetable on it before. You just can't foresee it with the setbacks. Hopefully, he doesn't have anymore."
Sunday's game will be made up as part of a doubleheader starting at 12:35 p.m. Monday. Jair Jurrjens will start the first game for Atlanta against Zach Duke, and Pittsburgh's John Van Benschoten will face Tim Hudson in the nightcap.
Duke and Jurrjens had been the scheduled starters Sunday.
Van Benschoten, who was called up from Triple-A Indianapolis when Matt Morris was released April 25, will make his first start of the season. He is 0-1 with a 4.91 ERA in three appearances.
Phil Dumatrait, who was originally scheduled to start Monday for the Pirates, will be pushed back one day along with the rest of the rotation. Pittsburgh begins a three-game series in St. Louis on Tuesday.
Sunday's game was called after a delay of 40 minutes. Light rain in the morning developed into a thunderstorm just before the scheduled 1:35 p.m. start. The tarp was never taken off the field.
Pirates general manager Neal Huntington discussed Wilson during his weekly radio show Sunday. He said the shortstop in getting some at-bats as a designated hitter. However, Wilson is still experiencing soreness in his injured calf and his biggest issues defensively are making quick starts and turns.
Once Wilson starts a rehab assignment, he might need as much as a week in the minor leagues.
"Jack is a competitor, and we want to get him up here and soon as we can," Huntington said. "We don't want to hold him back."
In Wilson's place, the Pirates have started three shortstops -- rookie Brian Bixler, Luis Rivas and Chris Gomez. Bixler has received the majority of the playing time, starting 18 of 33 games in Wilson's place, and was in the starting lineup before Sunday's game was rained out.
Russell said it has been difficult replacing Wilson, the longest-tenured Pirates player who hit .296 last season and was an All-Star selection in 2004. He's been missed most in the field. Bixler, Rivas and Gomez have combined for 11 errors at the shortstop position this season.
Wilson committed that many in 131 games in 2007.
"It's tough to be without your starting shortstop, especially when he's probably one of the best in the National League in fielding his position," Russell said. "I think you saw with the Phillies when they lost (Jimmy) Rollins for a while, it makes a big impact on your team."
The Pirates are 4-1 against the Braves this season and will finish with their first winning record against Atlanta since 1997. ... Pittsburgh has won five games in a row. The Pirates last won six straight in 2004, when they reeled off 10 in a row from June 26-July 5. ... Atlanta's Chipper Jones, leading the major leagues with a .400 average, is 1-for-11 in his past three games. His batting average has been above .400 since April 13.