England seamer James Anderson did not appear on day two of Lancashire's LV= Insurance County Championship clash with Somerset as he received treatment for a "minor issue".
Anderson was in outstanding form on the opening day at Emirates Old Trafford, taking 2-16 from 14 metronomic overs, but left the field shortly before rain brought an early end to proceedings.
The 40-year-old did not emerge with his team-mates on Friday, with Lancashire confirming he was experiencing an undisclosed complaint.
A spokesperson said: "Jimmy is off the field with a minor issue, which is currently being assessed."
England's record wicket-taker in Test cricket, with 685, is integral to their Ashes plans this summer, with bowling stocks already hit by fresh injuries to pace pair Jofra Archer and Olly Stone.
Archer has returned early from the Indian Premier League due to discomfort in his troublesome right elbow, while Stone faces several weeks on the sidelines after injuring his hamstring on duty for Nottinghamshire last week.
Anderson managed just four overs in the last home series against Australia, ruled out with a calf problem on the opening morning of the series.
England begin their Test summer against Ireland at Lord's, a four-day match starting on June 1, before the Ashes opener at Edgbaston on June 16.
In Anderson's absence, Lancashire's players combined to drop seven catches as teenager James Rew took centre stage, hitting 105 in Somerset's total of 361 all out, before Lancashire reached 72-2 in reply.
Tom Alsop's unbeaten century helped Sussex into a strong position against Leicestershire but Australia batter Steve Smith fell cheaply, out for just three off 14 balls as the game belatedly got going after a day-one washout.
Sussex still enjoyed a good second day as they made 319-4 after being sent into bat, with Alsop (118 not out), Cheteshwar Pujara (77) and James Coles (59no) leading the way.
Yorkshire edged their way into a controlling position against Durham, leading the hosts by 118 heading into day three at Seat Unique Riverside.
George Hill claimed four wickets to help bowl Durham out for 227, with Yorkshire reaching 91-3 in their second innings and England pair Dawid Malan (33 not out) and Jonny Bairstow (16no) at the crease.
Rory Burns led from the front with a fluent and aggressive 88 as Surrey chased a significant first-innings lead against Middlesex, trailing by only 19 runs on 190-3 at stumps.
But the most eye-catching innings of a second day cut short by bad weather was Jamie Smith's 55 not out, with the 22-year old showing off some memorable and high-class strokes.
Nottinghamshire seamer Brett Hutton took his third five-wicket haul of the season to compound former county Northamptonshire's ongoing batting woes.
Hutton found plenty of movement under floodlights, cloudy skies and light rain and precipitated a Northamptonshire collapse from 113-2 to 158 all out.
A fluent fourth-wicket stand of 68 between Joe Clarke (41 not out) and Matthew Montgomery (34) helped Nottinghamshire close one run behind on 157-4.
A buccaneering 10th-wicket stand of 70 restored Warwickshire's control after Essex fought back hard at Edgbaston.
Essex closed day two 86-4, still trailing by 30, after Warwickshire's last pair Hassan Ali (53 not out) and Olly Hannon-Dalby (18) clouted 70 from 69 balls to lift their side to 242.
A well-made 86 from Michael Neser and four wickets from Timm van der Gugten put Glamorgan within touching distance of their first win of the season against Worcestershire in Cardiff.
With Worcestershire ending the day on 195-7, 46 runs in front with just three wickets left, Glamorgan will be hoping to wrap up victory on Saturday.
Gloucestershire seamer Matt Taylor impressed on his first appearance of the season against Derbyshire, taking 2-18 from 10 overs as the hosts struggled on another day badly hit by the weather.
No play was possible until 2pm because of a wet outfield and - after Gloucestershire won the toss - Derbyshire reached 130-5 before bad light ended play early.
There was frustration for fans and players alike at Canterbury as a mere 6.1 overs were possible between Kent and Hampshire, with the visitors moving to 103-0 without loss, a lead of eight.
