Fick will be placed on the bereavement list on Wednesday and the Nationals will select the contract of outfielder Brandon Watson, who recently set an International League record with a 43-game hitting streak.
Per MLB rules, players placed on the bereavement list must miss a minimum of three games and a maximum of seven before returning to their club.
"I talked to Robert. He was shaken up," general manager Jim Bowden. "We told him to go ahead and go home to L.A. and, obviously, be with his family. We told him to take as much time as possible. His family comes first before baseball."
Fick is off to one of the slowest starts of his Major League career, hitting .217 with four RBIs. Fick said his slow start had nothing to do with the fact that his mother was terminally ill.
"Of course, [my mother's illness] has affected me, but the locker room and the baseball field is where I get my relief, so I don't want to blame my mother's illness on my slow start," Fick said on Monday.
Fick becomes the second player on the Nationals to be placed on the bereavement list this year. Closer Chad Cordero went on the list last month to be with his ailing grandmother, Josie, who eventually passed away.
"He already lost his dad, and now he has lost his mom," Cordero said about Fick. "It's going to be a difficult time for him. It will be good for him to go back home and be with his family."
Asked what advice he would give to Fick during his time of mourning, Cordero said: "Take some time off and get away from the game, so he can just be with his family. That helped me a whole lot."
As for Watson, he will start the next two games in center field, putting the Ryan Langerhans/Nook Logan platoon on hold. Bowden acknowledged that Watson's promotion is because of the hitting streak. The left-handed-hitting Watson was hitting .330 in 57 games at Triple-A Columbus.
"He's earned this promotion based on that alone, even though it was Triple-A pitching," Bowden said.
This is Watson's fourth stint with the Nationals. His first two opportunities came in 2005, but then-manager Frank Robinson didn't give him a chance, opting for Preston Wilson instead.
Last year, Watson started as the Nationals' center fielder, but was demoted by mid-April because of lack of production.
Members of the Nationals' think tank have always had mixed feelings about Watson. Some believe he could be a quality staring outfielder and others believe he is no more than a fourth or fifth outfielder.
"I haven't seen Brandon play. I've seen the Nationals play. I've seen college and high school guys. I've seen our A-ball clubs," Bowden said. "So all I know is, he's got a 43-game hitting streak, and anyone who can do that deserves a shot. But it's still against Triple-A pitching, so I say that cautiously. But you know, bring him up, and give him a chance. This is a great opportunity to do that."
To make room for Watson on the 40-man roster, the Nationals will move outfielder Alex Escobar from the 15-day to the 60-day disabled list. Escobar, who has yet to play a game because of right shoulder problems, had a setback. He sprained his right ankle recently in a Minor League game.
Escobar has been injury-prone since he arrived in Washington. First, he suffered a fractured right foot in 2005, and then he had a separated shoulder last year.
"It's frustrating." Bowden said. "I feel sorry for him because everybody wants to blame the player. It's not the player's fault when you get an injury. Maybe Escobar gets healthy, and for the next 10 years, he's healthy. I pray for him. I'm sorry for him, because nobody's more upset than he is, except for me."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.