Rob Gronkowski completed his latest trip through the operating room yesterday, as the Patriots tight end underwent back surgery. According to several sources, the procedure, technically a microdiscectomy performed by noted spine surgeon Robert Watkins in California, went well. One source noted the surgery was a “standard disc repair.” Watkins was expected to remove a portion of Gronkowski’s troublesome disc. The tight end now begins the recovery process, which might run into the start of the regular season. It’s expected he won’t be ready for beginning of training camp, which is at the end of July. His status for the first game of the season Sept. 8 and beyond remains in question. The common amount of time needed for athletes to be game-ready after this type of procedure is 12 weeks, meaning Gronkowski might start the year on the physically unable to perform list. That would require him to miss the first six games of the season, and given Gronkowski also is rebounding from four surgeries on his left forearm (all since November), the cautious approach might be the most prudent. Gronkowski has been progressing well from the most recent forearm surgery he had last month. According to a source, cultures have not shown any signs of more infection. Naturally, if Patriots coach Bill Belichick feels Gronkowski is close enough to being game-ready before Week 7, he won’t place the tight end on the PUP list. But that is a long way down the road right now. This is the second time Watkins has performed surgery on Gronkowski’s back since he was in college at Arizona, so there will be plenty of attention paid to any symptoms or warning signs in the coming weeks.