The England batsman was included in Warwickshire's squad against Nottinghamshire, for whom Alex Hales again showed his affection for Edgbaston with a season's best 183 after the home side won the toss and decided to bowl first on the opening day - with Hales helping his side to 397 for seven by stumps.
Trott made an important breakthrough on the stroke of lunch when, with his 17th ball, he took his first championship wicket in four years as Phil Jaques edged one that was angled across him to wicketkeeper Tim Ambrose for 77.
Also in Division One, Paul Horton returned to the scene of his highest score for Lancashire to hit a fighting century on the opening day of the match with Somerset at Taunton.
The 31-year-old opener, who scored 173 in the corresponding match five years ago, played a solo hand with 140 as his side struggled to 221 for six, having won the toss. None of the other batsmen reached 20.
Horton faced 256 balls and hit 21 fours. But Jos Buttler's hopes of a big score on his first return to the County Ground since leaving Somerset were scuppered when he fell for 18.
Nick Gubbins, a 20-year-old left-hander from Richmond, made 54 on his championship debut as Middlesex reached 280 for three on a weather-affected first day against Northamptonshire at Lord's.
Gubbins, given his chance because England's management have chosen to rest Sam Robson from this round of games along with most of the Test team beaten by Sri Lanka at Headingley, put on 128 with Chris Rogers for Middlesex's first wicket after they had been put in.
In Division Two, Tom Fell scored his second consecutive LV= County Championship hundred in an immediate tribute to his mentor, Damian D'Oliveira, who died only hours before the fixture with Glamorgan at New Road.
In a partnership between two of the many graduates from D'Oliveira's Academy, Fell (133) and Tom Kohler-Cadmore (60 not out) put on 168 as Worcestershire recovered to reach 266 for five after early problems on a sombre morning for the county.
A sparkling unbeaten 114 by the in-form Jason Roy coupled with half-centuries from Tillakaratne Dilshan and Gary Wilson helped Surrey dominate a rain-interrupted second day against Hampshire at The Oval.
Five rain delays failed to hamper Surrey's flow or curtail an eye-catching unbroken sixth-wicket stand between Roy and Wilson which added 159 in 33.1 overs through to stumps.
Reece Topley provided further proof of his blossoming talent with an impressive five-wicket haul before Essex let opponents Gloucestershire off the hook on the opening day at Chelmsford.
The 21-year-old left-arm seamer made use of the greenish pitch to claim his successes at a personal cost of 53 and in doing so went some way to confirming that he has overcome a stress fracture of the back which forced him to miss the first six Championship games of the season.
Now playing his third Championship match of the summer, he has bagged 20 wickets - including 10 in the match against Glamorgan on his return to four-day cricket - as the hosts bowled Gloucestershire out for 224 before reaching 75 for no loss by stumps.
- Sports & Recreation
- Alex Hales
- Paul Horton