The 31 year old has picked up an achilles injury, it's severity hasnt been annouced, but it looks severe enough to push Paul Warne into the transfer market to fill his boots.
"It's been evident that we can't rely on Joe to play 50 games every season. I'm looking forward to hopefully bringing in a new left-back next week." Warne told the Advertiser.
Mattock sat out the Grimbsy win yesterday; "I got told that he felt like his achilles was really tight, He was a bit tired from Tuesday night. He trained on Friday and the intention was for him to play a part today. I intended to shuffle things around. But he wasn't fit to join the play. He's been struggling with an ankle for quite a bit now."