D'Arnaud (hand) is on track to begin a rehab assignment by the middle of next week, Adam Rubin of ESPN New York reports. The 26-year-old catcher worked quickly through his hitting progression this week, going from dry swings Monday to full batting practice Friday. D'Arnaud is now looking ahead to a rehab stint, and while it's uncertain how long his stay in the minors could last, he appears headed for an early-June activation.