"At least one person close" to Borland thought he would "seriously consider" retirement after his rookie season due to his overall physical health, the report says. Multiple NFL teams also reportedly took Borland off their draft boards last year due to concerns over chronic issues in both shoulders.
Borland had three shoulder surgeries in four years at Wisconsin, two on his left shoulder and one on his right. The San Francisco 49ers selected him in the third round of last year's NFL draft.
Borland went on to have a productive rookie season, leading the 49ers with 108 tackles while playing in 14 games (eight starts), receiving Defensive Rookie of the Month honors in November and the NFC Defensive Player of the Week award in Week 11.
In the news story announcing his retirement on Monday, Borland told ESPN's "Outside the Lines" that he begun considering retirement after thinking he sustained a concussion during training camp last summer. Borland's father, Jeff, told Mike Garafolo of FOX Sports on Tuesday that he knew this might be his son's only year in the NFL.
"I just honestly want to do what's best for my health," Borland said in the story. "From what I've researched and what I've experienced, I don't think it's worth the risk."
San Francisco linebacker Patrick Willis, 30, also announced his retirement last week. Borland was considered likely to replace Willis as a starter for the 49ers, but told "Outside the Lines" that Willis' retirement did not have a role in his decision.
- Mike Fiammetta