NEW YORK - There was a sense of optimism around the Phillies in recent days that Maikel Franco would return to game action before season's end. The rookie third baseman had taken ground balls and played catch for more than a week without pain in his left wrist.

But that optimism was tempered Wednesday afternoon when Franco took 20 pitches of soft toss in a Citi Field batting cage. The same discomfort Franco had experienced resurfaced when he swung through the ball. The Phillies could shut him down for the season if his wrist does not improve over the next week.

"Unless he's 100 percent, we're just going to be careful," interim manager Pete Mackanin said.

Wednesday's swings were Franco's first since the Phillies placed him on the 15-day disabled list with a broken wrist on Aug. 18. The DL stint is retroactive to Aug. 12, the day after he was hit by a fastball in Phoenix, so he is eligible for activation at any time.

Mackanin said Wednesday he thought the chances are "probably 50-50" on whether Franco will play again this season.

Those odds might be generous. The last-place Phillies will exercise caution with their 23-year-old third baseman of the future. Only 28 games remain on the team's schedule after Wednesday's series finale against the New York Mets.

"It's not good for me, because I want to play," Franco said when asked how disappointed he would be if he could not return this month. "But I have to take it and I have to understand my situation right now."

Franco hit .277 with an .830 OPS over 296 at-bats before his injury. Eight home runs and 24 RBIs in June helped earn him National League rookie of the month honors. He could make up at-bats in his native Dominican Republic during winter ball.

Ruf vs. lefties

The Phillies are set to face two more lefthanders this weekend in Boston, meaning Darin Ruf will all but certainly garner two more starts at first base.

Ruf has taken advantage of his starts against southpaws with a .337 batting average and a 1.062 OPS this season. He drove in a career-high six runs on Tuesday, four off Mets starter Jon Niese. He is 2 for 4 with a double and an RBI lifetime against Boston's Wade Miley, who will start Saturday. No Phillies player has faced rookie Eduardo Rodriguez, who pitches Sunday.

Extra bases

Darnell Sweeney made his first major-league start in left field and hit a home run. The new Phillies utility man had 19 games of experience in left, all this season with triple-A Oklahoma City. . . . Reliever Jeanmar Gomez has allowed nine earned runs over his last 92/3 innings after giving up only 13 over his first 561/3 innings of the season.

- Jake Kaplan