Woods had to withdraw from the tournament unfortunately due to a neck strain which he has classified as not too serious, but something he wanted to avoid stressing at the start of the season.
He had previously announced this week's Arnold Palmer Invitational and next week's Players Championship as his next starts.
Day said he hoped to be ready to play next week's Players Championship, which he won in 2016.
The 43-year-old, eight-times victor of the tournament at Bay Hill in Orlando, announced on Twitter that he had been struggling with the problem for some time.
He continued in a follow-up tweet: "I'd like to send my regrets to the Palmer family and the Orlando fans".
US Shutters Its Consulate in Jerusalem, Angering Palestinians
Anadolu Agency was unable to obtain immediate comment from either Palestinian or Israeli officials regarding Lavrov's assertions. Palestinian official Saeb Erekat called the move "the final nail in the coffin" for the US role in peacemaking.
"I hope he's OK", continued McIlroy, who is the defending champion at Bay Hill this week.
Day said he still aims to recover in time for next week's Players Championship at TPC Sawgrass. The 43 year old has played the tournament 19 times.
Injuries are once again catching up to Tiger Woods. He took last week off after playing in the WGC tournament in Mexico.
Tiger Woods set golf's alarm bells ringing on Monday night by pulling out of this week's PGA Tour event with a neck injury.
The American's last win was in 2013 when he shot 13-under 275 for a two-stroke victory.
He competed 18 times on the PGA Tour a year ago, winning the Tour Championship for his 80th PGA Tour title.