 -- Defensive end Shaq Lawson, who was selected by the Buffalo Bills with the 19th overall pick in the NFL draft, will have shoulder surgery, the team announced Monday.

Lawson had insisted after the draft that he wouldn't need surgery, but the Bills on Monday said they would go ahead with the procedure on Tuesday as a preventative measure.

Sources told ESPN NFL Insider Adam Schefter during the draft that the procedure would sideline him for four to six months, which would mean the former Clemson standout wouldn't return until mid-September to mid-November.

"The Buffalo Bills are taking measures to prevent the possibility of Shaq Lawson aggravating a pre-existing shoulder condition during the season," the team said in a statement. "While he could continue to play, the Bills medical staff has determined that surgery is the best course of action for the overall health of his shoulder moving forward."

The Bills said in the statement that Lawson had an occurrence of the condition last week but was still moving forward with the idea that he would participate in the offseason program.

"I want to take this opportunity to commend Shaq Lawson and his representatives for putting the team first by having this surgery on his shoulder done now," Bills general manager Doug Whaley said in a statement. "By doing so, he's forsaking personal goals to be 100 percent healthy when we will need him most during the regular season.

"Fans constantly hear us say that we want players with tremendous character who keep team goals ahead of personal ones and Shaq is a great example of this."

Lawson was adamant after the draft that he suffered the injury during his freshman season at Clemson in 2013 and that he could play without the surgery.

"If I didn't have surgery my freshman year, why would I need surgery now?" Lawson said then. "I can still play ball."

Added Whaley after the draft: "[Our] medical staff cleared him, said he can play. Now, if something happens, it's going to happen. But it's nothing that we're real worried about or we wouldn't have taken him. We got complete faith in our medical staff and they signed off on him, so we're excited to have him."

Lawson said his shoulder was flagged by the Jacksonville Jaguars for a follow-up during February's scouting combine, necessitating a return trip to Indianapolis for a medical re-check earlier this month. One of the draft's top pass-rushing prospects, Lawson told ESPN that teams were encouraged by the re-check.

The Bills had hoped that Lawson could become an immediate starter at outside linebacker in Bills coach Rex Ryan's 3-4 defensive scheme.

ESPN Bills reporter Mike Rodak contributed to this report.