EDEN PRAIRIE, Minn. (AP) — Minnesota Vikings center John Sullivan is still recovering from a back injury that has kept him out for nearly three weeks, but coach Mike Zimmer said he’s encouraged by the progress that has been made by the anchor of the offensive line.

Sullivan was not on the field Monday for practice, as the Vikings began preparation for their regular-season opener at San Francisco. But Zimmer said he wasn’t concerned about Sullivan’s status this week.

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“Not really. He’s getting better every day, so we might get him out here a little bit tomorrow,” Zimmer said. “We’ll see.”

Sullivan, the second-longest tenured player on the offense behind running back Adrian Peterson, has been the starter since 2009, his second year in the NFL. He has not missed a game since Oct. 23, 2011, a streak of 58 straight starts including one in the playoffs.

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Sullivan has not taken part in practice since Aug. 18. Joe Berger has been filling in, leaving the Vikings without their top backup. They were already down one starter when right tackle Phil Loadholt tore the Achilles tendon on his left foot Aug. 15.

“That’s what preseason is for, to kind of get used to that shuffle in case it has to happen at some point.” Berger said. “Obviously you want the starting five to be healthy the whole year, but that’s reality in the NFL in most cases anyway.”

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