Morse likely will begin the season on the disabled list, Manager Davey Johnson implied again today, but how long he stays there could be determined by today’s events. Morse planned to throw this morning. Afterward, he will receive a sonogram to check for tears in the strained right lat muscle that has sidelined him for the entirety of spring.

If the sonogram reveals no further tearing, Morse will begin hitting off a tee and ramping back up to full baseball activities. Morse could begin playing in minor league games by the weekend, but the Nationals likely won’t play him in major league spring training games in order to keep him eligible to return from the disabled list as early as possible.

“Say he starts going full-bore in a week, he could be playing that last week in some games,” Johnson said. “But with that kind of injury, maybe they want to have his at-bats in warmer weather. It’s possible if we backdate him, he’d miss about a week. I can live with that.”

A player who starts the season on the disabled list can return as early as April 10, so long as he did not play in a major league spring training game on March 26 or later.

Johnson said Morse could head north with the Nationals from Florida, then report to either Class A Potomac or Class AA Harrisburg. (Although, because both affiliates start on the road, Morse more likely would play at Class A Hagerstown should the Nationals choose to send him on a minor league rehab assignment.)

The strain first affected Morse on March 6, when he was scratched from the Nationals’ lineup. He returned as a designated hitter March 12 and 13, but further discomfort necessitated the PRP injection. Morse has played just three games this spring, none in the field.

The Nationals are more optimistic about Adam LaRoche’s recovery from the bone bruise in his left foot by opening day. They cleared him to run bases fully today, making “inversion turns” with his sore ankle. If all goes well, Johnson said, LaRoche could return to major league games today. LaRoche has played in several minor league games this week.

Two other minor injury notes: Center fielder Rick Ankiel should return by Friday as he battles lingering tightness and soreness in his left quadriceps. Utility man Mark DeRosa did not make today’s trip after feeling cramps in his calf. “He said he wanted to go,” Johnson said. “I told him, ‘You can come sit with me.’ ”