Rosario did see action on the bases on Saturday against Cincinnati, entering as a pinch-runner after pinch-hitter Jacob deGrom walked in the seventh inning. He scored on Norichika Aoki's two-run single.
The swelling in the 21-year-old's finger had gone down considerably from when he first bruised the digit on Sunday in Houston. Rosario participated in a full range of baseball activities, including swinging in an indoor cage, on Saturday before the game.
When Rosario returns, the Mets remain wary of an errant pitch causing the swelling to return.
"It's not going to be caused by hitting off the tee or [taking] batting practice," Collins said. "It's going to be caused by someone throwing a 95-mph fastball on your fist. So that's what he's got to be able to deal with."
In 31 games since his Aug. 1 callup, Rosario is batting .245 with four home runs, four stolen bases and a .699 OPS. He projects as the Mets' Opening Day shortstop in 2018.
Noah Syndergaard, who pitched two innings in a rehab start for Class A Brooklyn on Thursday, will throw approximately 50 pitches Sunday in a simulated game at Citi Field. The Mets have not determined when Syndergaard's next rehab outing will be. He is recovering from a torn right lat muscle, which has sidelined him since April 30.
Anthony DiComo has covered the Mets for MLB.com since 2008. Follow him on Twitter @AnthonyDiComo and Facebook. This story was not subject to the approval of Major League Baseball or its clubs.