Free-agent offensive tackle Andre Smith has agreed to a one-year deal with Vikings. Smith announced the deal himself via Twitter. The contract could be worth up to $4.5 million, with $1 million guaranteed, per a source.

Smith visited the Vikings on Sunday and Monday but left the Twin Cities without a deal. He told the Pioneer Press he next planned to visit the Cardinals, but it doesn't sound like the Cardinals were aware of his plan.

As our Sunday story pointed out, the Vikings are certainly focusing on improving their offensive line. And the addition of guard Alex Boone and now Smith should lead to some interesting battles in training camp.

Smith will presumably duke it out with Phil Loadholt, who has missed much of the past two seasons because of injuries, and last year's starter, T.J. Clemmings, for the right tackle spot. Mike Harris might also get in the mix.

Smith, Loadholt and left tackle Matt Kalil will all have one year remaining on their contracts. Loadholt's restructured deal included no guarantees.

Smith was the sixth overall pick in the 2009 draft and spent his first seven seasons with the Bengals. Vikings coach Mike Zimmer was the defensive coordinator in Cincinnati for five of those seasons.

The 6-foot-4, 335-pound right tackle has made 73 career starts.