He posted the following two tweets.
Fans may remember that the field grass at Levi's Stadium had numerous issues with loose sod last season.
The 49ers are scheduled to have eight consecutive practices at Levi's Stadium.
Tim Kawakami of the Mercury News also pointed out issues with the field tonight.
And later from Matt Maiocco of CSN Bay Area...
And even later from Cam Inman of the Mercury News...