OVER THE LAST 15 games, the Phillies' offense has not been putrid, and it has not been putrid while facing some pretty good teams.

In helping win nine of the last 15 games, the lineup has scored four or more runs in seven games (an accomplishment, believe it or not), while posting a respectable .272/.327/.407 line.

Chase Utley's numbers during that stretch: a .295 batting average, .404 on-base percentage, .432 slugging percentage, five runs and four RBI.

Starting tonight against the Nationals, those numbers will no longer be at the Phillies' disposal. Last night, the Phillies placed Utley on the disabled list with what they described as a "very mild" oblique strain that is expected to sideline the second baseman for 2 to 4 weeks.

The official statement released by the Phillies took an optimistic view, noting that an MRI exam conducted yesterday did not reveal any injuries to the intercostal or rib-cage areas.

"We do believe and hope that Chase will be ready to play in Philadelphia within 15 days," general manager Ruben Amaro Jr. said in a statement. "We are being cautious with this injury as it is a tricky one and want to make sure it isn't an issue for him throughout the season."

The big question is whether the Phillies will have a meaningful season to play when Utley returns. The team has yet to win more than three straight games this season, and has not spent a single day with a record above .500. Utley is one of a number of trade chips the Phillies could decide to shop in an effort to fortify their talent base for the future. But a recovery toward the 4-week end of things would get him back on the field around June 21, roughly 5 weeks before the July 31 nonwaiver trade deadline.

Given the intricate nature of the trade talks the Phillies would need to have - all of their marketable stars have significant no-trade clauses, and most have salaries that would require money to change hands in any deal - they likely will have to decide on a big-picture strategy at some point in that relative time period.

Filling in for Utley will be 23-year-old utility man Freddy Galvis, who has performed well in limited action this season. He is 19-for-69 with three doubles, three home runs, 15 strikeouts and five walks in 75 plate appearances. The three home runs are the same number he logged in 200 plate appearances last season, when he spent the first 3 months of 2012 filling in for Utley as he attempted to get his knees in shape.

Late last night, the Phillies called up former Rule 5 pick Michael Martinez to help fill the void left by Utley.

And now the Phillies will spend at least 2 weeks without the player who has been their most productive hitter this season. Turning around the offense just got a little harder.

Today on PhillyDailyNews.com: David Murphy writes about Phillies prospect Andrew Pullin from down in Clearwater.

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