Matt Maiocco, of the Santa Rosa Press Democrat, reports San Francisco 49ers head coach Mike Nolan said TE Delanie Walker (shoulder), OG Justin Smiley (shoulder), OG Eric Heitmann (leg), OT Jonas Jennings (shoulder), CB Shawntae Spencer (foot) and WR Darrell Jackson (toe) will likely be held out of the team's OTAs, which begin June 4.

Information from KFFL.com

Matt Maiocco's blog can be found here:
http://49ers.pressdemocrat.com