According to Matt Maiocco of CSNBayArea.com, San Francisco 49ers Pro Bowl tight end Vernon Davis and second-year wide receiver Michael Crabtree were engaged in an animated discussion during the team's walk-through, which required the intervention of head coach Mike Singletary.

Via Maiocco's Twitter feed:

11:43am PST: "Very interesting scene off to side of practice field with Singletary moderating animated "discussion" between Vernon Davis and Crabtree."

11:48am PST: "And now Singletary takes Vernon Davis and Crabtree inside locker room while rest of 49ers continue with walk-through."

11:57am PST: "Vernon returns solo to field."

12:06pm PST: "And now Singletary and Crabtree return from locker room."

Maiocco concludes by saying that there "were definitely words" between Crabtree and Davis, and that Singletary deviated from his normal course of action by taking the team inside to address them following practice.

Matthew Barrows of the Sacramento Bee reports that Davis was the more animated of the two.

Should be interesting to see what, if anything, develops from this.