Westbrook signed a contract with the Giants on Monday, which includes an invitation to spring training, Amy Gutierrez of NBC Sports Bay Area reports.
Westbrook was previously in Arizona's farm system, where he hit .321 with three home runs and 18 RBI over 30 contests at Triple-A Reno in 2019. He suffered a knee injury in mid-August but should be ready to roll for spring training.
Westbrook suffered a minor knee injury in Sunday's Double-A action, Zach Buchanan of The Athletic Arizona reports.
Westbrook's injury doesn't appear to be serious, but he'll be held out for at least a week as a precaution. Through 107 games at Double-A Jackson, he's put together a .287/.336/.471 slash line with 15 homers and 68 RBI.
Westbrook, 20, is slashing .294/.353/.399 with two home runs, 15 RBI and three steals in 41 games for Double-A Mobile.
The toolsy Westbrook has not been overwhelmed at this level despite his young age. He has been particularly hot lately, batting a scalding .474 with two home runs and 10 RBI over his last 10 games. He's small and has questionable defensive skills, but should still be on the prospect radar right now.