SANTA CLARA, Calif. (AP) -- Ryan Seymour was standing on the visitor's side of Candlestick Park on Sunday.
Two days later, he found himself sharing a locker room with the opponent.
The San Francisco 49ers announced Tuesday they signed Seymour from the rival Seattle Seahawks practice squad to a three-year contract as insurance at the left guard position.
Starter Mike Iupati has missed the past three games with a sprained left knee and left tackle Joe Staley returned for Sunday's win against the Seahawks a week after spraining his right knee.
Seymour was surprised by a Monday morning telephone call from his agent, saying he was on his way back to San Francisco.
The 49ers (9-4) placed defensive tackle Tank Carradine on injured reserve and signed wide receiver Devon Wylie to the practice squad.
''I wasn't expecting, this late in the season, to be called up by a team,'' Seymour said after his first day of practice with the 49ers. ''I'll certainly take advantage of my opportunities.''
Seymour was the last man off the practice field as he tried to learn as much of the offensive system as he could.
The rookie from Vanderbilt is listed third on the 49ers' depth chart at left guard behind Iupati and Joe Looney.
Iupati went through practice and said his knee felt better, but that he still considers himself ''day to day.''
Seymour, drafted by Seattle in the seventh round, was released by the Seahawks and then added to their practice squad in early September.
''We got home late Sunday and my agent called at 6 a.m.,'' Seymour said. ''I made the same flight 24 hours later.''
He was on the sideline at Candlestick Park during the Seahawks' 19-17 loss to the 49ers on Sunday.
''It might have been easy just to walk across the field,'' he said. ''But I did have some packing to do and I had to take care of a few other things.''
Seymour played every position on the offensive line during his days with the Commodores, which makes him valuable. Staley and right tackle Anthony Davis do not have a backup listed and Adam Snyder, normally a right guard, started on the left side for Iupati.
The 49ers' offense rushed for 163 yards on 33 carries against the Seahawks defense that was allowing 107.2 yards. Running back Frank Gore picked up 51 of those yards on a play late in the game that set up the go-ahead field goal.
''It was a play that we saw at one point that we thought could be a good play for us,'' 49ers center Jonathan Goodwin said. ''Fortunately for whatever reason it got held until the end of the game and it popped big for us. Frank made a nice cut.''
Seymour becomes one of nine rookies on the 49ers depth chart, though free safety Eric Reid is the only starter of the group.
NOTES: Reid celebrated his 22nd birthday Tuesday. ... CB Eric Wright appeared in his fourth game since being activated from the Reserve/NFI list on Nov. 11. ''I'm just trying to recover from playing on Sunday,'' he said. ''It's a positive to be playing now but a bit of a negative to be jumping into a role and trying to be in late-season form. For me, it was the equivalent of, maybe, my first game.'' ... The 49ers have a 16-5 advantage in their series with the Tampa Bay Buccaneers, including 4-3 in Florida. They last played on Oct. 9, 2011, in San Francisco, a 48-3 49ers victory.
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