By Tony Jimenez WATFORD, England (Reuters) - Former world number one Luke Donald spoke with the benefit of experience on Tuesday when the Briton suggested Tiger Woods may have to simply grit his teeth and commit to a definite comeback date. Fourteen-times major winner Woods, out for 14 months due to back-related issues, announced this week his game was not sharp enough for a return at the PGA Tour event in California starting on Thursday or at next month's Turkish Airlines Open. Donald knows the psychological barrier the 40-year-old American has to overcome because the Englishman was sidelined for five months in 2008 after sustaining an injury to his left wrist. More...