Getty Images

Veteran designated hitter J.D. Martinez signed with the New York Mets on Thursday night, ending his prolonged stay on the free-agent market. Just don't expect to see Martinez in the lineup come March 28, when the Mets open their regular season campaign with a series against the Milwaukee Brewers

Rather, Martinez has agreed to be optioned to the minors so he can see live pitching and shake off the rust that comes from missing out on nearly the entire exhibition season. (For clarification purposes: players with more than five years of service time, and Martinez has more than 12 years, must consent to optional assignments.) Players on optional assignments are required to spend at least 10 days in the minors, meaning the earliest Martinez can slot into the Mets lineup will be April 7.

Martinez, 36, spent last season with the Los Angeles Dodgers. He hit .271/.321/.572 (134 OPS+) with 33 home runs and 103 RBI. His contributions were worth an estimated 1.9 Wins Above Replacement, per Baseball Reference's calculations. He's a six-time All-Star who clearly wants to play beyond this season. 

For evidence of that last statement, consider what he told reporters when explaining why he resisted signing with the San Francisco Giants and playing his home games at Oracle Park, an unforgiving hitting environment. "If I go there and I hit .260 with 20 [home runs]," Martinez told MLB.com, "people are going to say that I'm old and I'm washed up and I'm kind of done, and [I'll] find myself out of the game. I wanted to give myself the best opportunity."

Jon Heyman of the New York Post reported in February that Martinez rejected an offer from the Giants because he "didn't want to go there." The Giants subsequently signed Jorge Soler to serve as their DH.

Per Statcast's three-year park factors, Oracle Park is the fourth-worst park for right-handed home runs. Citi Field, while still unfavorable to right-handed batters compared to the average ballpark, ranks 21st in that respect.