Tykes worry over Sidebottom
Yorkshire are hoping Ryan Sidebottom's hamstring injury is just a "little tweak" - but they will take no chances with him against Lancashire.
Sidebottom was unable to bowl after lunch on day two, as Lancashire reached 325 all out in the LV= Division One match despite five wickets for Jack Brooks and four for Liam Plunkett.
England seamer Tim Bresnan, meanwhile, mustered just the remaining success in the innings but had to get through 27 overs in Sidebottom's absence as the Red Rose resisted.
Yorkshire coach Jason Gillespie explained, after his team had closed on 29 for none, that he is optimistic Sidebottom's injury is only minor.
"He's just felt something at the bottom of his hamstring, so it will be an ongoing assessment of that," said the former Australia fast bowler.
"We will make a decision on whether we need to get him scanned, and we'll probably know more tomorrow and make a plan from there.
"At this stage, it looks like a little tweak, and we don't think it's serious - but we've got to look after him."
Sidebottom was wicketless but impressed in the morning session.
"He bowled a couple of balls at lunchtime but he was feeling it a little bit," added Gillespie.
"With 'Siddy' being such an important member of our squad, the leader of our attack, we want to make sure he's 100 per cent."
Gillespie was encouraged that the Yorkshire attack performed better at their second attempt than they had in the one session possible because of rain on day one.
"It was an improvement on yesterday, because we didn't bowl well then.
"The lads put their hands up and said they could do better.
"I still think we can bowl better than that, but it was an improvement.
"If we bowl to our potential I think we could have restricted them a bit more.
"But we've started well with the bat; it's a good pitch - and we're looking forward to putting a good score on the board."