Yakubu, 33, lives close to Wood's ground and played in Saturday's friendly versus former club Reading.
"He's like a Rolls Royce, especially at this level. When he lands on the ball he's phenomenal," said Garrard.
"Is he as sharp as he used to be in the Premier League? No, but at 33 he could definitely do a job in the League."
Yakubu has scored more than 140 goals in his career for clubs also including Middlesbrough and Blackburn and has returned to England after a spell in the Turkish top flight with Kayserispor.
Garrard got in touch with the forward through a mutual friend and invited him down for two training sessions, before he appeared in the match against the Royals.
"I can imagine he's got interest especially after he'd been with us and played against Reading, so I can imagine something will happen in the next week or so but until then we'll enjoy his company," Garrard told BBC Sport.
"It's a long shot (signing him for Boreham Wood).
"I spoke to him on Sunday and he was very open in terms of a few bits that are going on but I've heard a little rumour someone in the League has put an offer to him so it will be very interesting to see how that pans out."
Boreham Wood manager Luke Garrard admits signing Yakubu is a "long shot", despite the ex-Nigeria and Everton striker training with the club.