UFC 158 Update: TJ Dillashaw in for Mitch Gagnon

The Ultimate Fighting Championship started 2013 strong with few injuries, but the UFC 158 fight card, just one month away, has suffered a couple of casualties this week alone… and it's only Tuesday.

Following a reshuffling of the main card after Rory MacDonald withdrew due to injury, the preliminary fight card also took a hit when Canadian Mitch Gagnon, also injured, fell of the card.

TJ Dillashaw has already agreed to step in for Gagnon to square off with Issei Tamura. The move was first reported by the Canadian Press and later confirmed by UFC officials.

Dillashaw (7-1) enters the bout riding a wave of momentum. After losing in the TUF 14 Finale in laste 2011, Dillashaw went two-for-two last year, defeating Walel Watson and Vaughan Lee. He was expected to return at UFC on Fox 5 in December, but was forced off the card due to injury.

Healthy and ready to go, he now steps in against Tamura (7-3), who is looking to get back on track. After knocking out Zhang Tiequan in his Octagon debut, Tamura was on the wrong end of the knockout when he fought Raphael Assuncao last July.

The Assuncao bout was also Tamura's first at bantamweight, which is where he'll meet Dillashaw to try and capture his first victory at 135 pounds.

UFC welterweight champion Georges St-Pierre headlines UFC 158, putting his belt on the line against Nick Diaz on March 16 at the Bell Centre in Montreal.

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