On Monday she was also named in Vlatko Andonovski's USWNT squad for the SheBelieves Cup.
Morgan, 31, hasn't trained with the Pride since August 2020 when she returned to them after giving birth to her daughter Charlie ahead of the Challenge Cup.
However, the Pride were unable to compete in the Cup due to COVID-19 cases in the squad and Morgan secured a move to Tottenham in September for the first half of the 2020-21 Women's Super League season.
"Mentality going into 1st day of pre season... and every day after that!," Morgan wrote on Instagram, accompanied by a picture of her in the Pride dressing room wearing a jumper with the letters: LFG [Let's F------ Go].
Morgan had the option of extending her contract with Spurs until the end of the season but instead opted to return to the United States for the NWSL season.
Morgan was not included in Andonovski's January camp after she confirmed she had contracted COVID-19 over the Christmas holidays.
"Unfortunately, my family and I closed out 2020 learning that we had contracted COVID while in California over the holidays," Morgan, a native of Southern California, posted on social media.
"We are all in good spirits and recovering well. After our isolation is completed, I will follow US Soccer's return to play guidelines to ensure my body is fully recovered and I can join my teammates back on the field soon. Be safe and happy new year."