"It got to the point where Wil felt that it wasn't progressing to keep going down this path of [being] day-to-day," said Padres manager Bud Black.
Myers has missed the past seven games, including Tuesday's series opener against the Cubs.
The tendinitis is near the extensor carpi ulnaris, a muscle located on the little finger's side of the forearm that is used to extend the wrist.
"It's really tough to do that -- to play at a high level, at the high level I can -- with this wrist injury," Myers said. "We felt that, with me getting 100 percent healthy, it's better than trying to push it right now. If we can get me back to where I was to begin with, that's when I'll play."
Black said that Myers initially hurt the wrist sliding into a base May 10 against the D-backs, and when he placed his left hand on the ground during the slide.
Myers, who is hitting .291 with five home runs and 19 RBIs, has had issues with his wrists in the past, but this isn't the right wrist he broke in an outfield collision last May while with the Rays.
Myers has a bone spur on the back of his wrist that essentially rubs against the inflamed tendon, and he said he's had the bone spur since middle school. He jammed his left wrist four games into the 2014 season, but that eventually healed while he was on the DL.
"Last year, I really pushed it," he said. "I just wasn't the player I know I can be. But with this injury, I know that if I can get this to where it needs to be, we'll be a better team than with me trying to play through it."
A trip to the disabled list was the last thing Myers expected, but all involved realize it's the best thing for him right now.
"He needs rest, that tendon needs rest," Black said. "It needs to calm down. There's no timetable for his return. It's unique to every individual how they come out of an injury. We know it's sore, and it's painful when he swings."
Abraham Almonte and Cory Spangenberg have handled the leadoff spot with Myers down, but those two have largely struggled in a small sample size (six games).
Heading into Tuesday's game, Almonte and Spangenberg are hitting a combined .182 (4-for-22) and have 10 strikeouts. Spangenberg hit leadoff on Tuesday against the Cubs.
Myers was leading the team in hits (39) and runs (28) at the time of his injury.
The Padres recalled right-handed pitcher Cory Mazzoni from Triple-A El Paso to take Myers' spot on the 25-man roster. This is Mazzoni's second big league stint. He allowed six earned runs in two innings in two games last month.