Kent 180 (Bell-Drummond 84*; Mullaney 3-2, Pattinson 3-30) and 105 for 4 trail Nottinghamshire 371 (Mullaney 168, Hales 85, Coles 3-99) by 86 runs
With doubts lingering over Stuart Broad's fitness for Saturday's Royal London One-Day Cup final at Lord's, Nottinghamshire face another anxious couple of days assessing the fitness of a second key bowling asset after injury forced Jake Ball to leave the field during the final session here.
Despite playing the injury down overnight, Ball was sent for a scan by the ECB on Wednesday morning, and the selectors will be monitoring the results closely as they prepare to meet to select the squad for the first Test against South Africa at Lord's next week.
The England fast bowler, who had already struck an important blow for his team in this match at the start of Kent's second innings, pulled up in his follow-through after bowling one delivery of his third over, feeling some pain in his right knee.
After receiving attention on the field it looked at first as if he would continue but after a couple of attempts to replicate his run-up to the crease under the supervision of his county physio he asked the umpire for his cap and sweater and left the field, leaving Luke Fletcher to complete his over.
Nottinghamshire head coach Peter Moores described his withdrawal as "a precaution" and said his prospects of resuming in this match would be assessed in the morning. However, he is being monitored by Notts and England medical teams, and he will not bowl again in the match.
Broad, who was forced to miss this match after suffering a heel injury against Leicestershire last week, was still rated as doubtful on Monday but there was better news today. Put through his paces before play, he appeared to be moving well enough, although Nottinghamshire will be wary of risking any further damage with the opening Test against South Africa just over a week away.
After playing his part with a flurry of boundaries with the bat in helping Nottinghamshire to a lead of 191 on first innings, Ball had dealt Kent the early blow they least wanted as they began their second innings against the pink ball in the awkward day-to-night phase.
After bowling brilliantly with scant reward in the first innings, with only one tailender's wicket to show for his efforts, Ball found success in his second over this time, producing a full and fast delivery to which Daniel Bell-Drummond, who had so valiantly held Kent together on Monday, had no answer.
Yet Ball's absence hardly made things easier for Kent, who were four wickets down and still 86 behind at the close. To make matters worse, Sam Billings, unbeaten on 39, now leaves this match to play for the Lions at Worcester. The 20-year-old batsman Joe Weatherley takes his place.
Despite a career-best 168 from Steven Mullaney, who was 63 not out overnight, and a partnership of 222 between the opener and Alex Hales, Nottinghamshire had not fulfilled their objective of batting Kent out of the game, losing their last wickets for 41.
They fell short even of maximum batting points, which felt almost like a formality earlier in the day when Hales and Mullaney, having come through a tough pink ball baptism on the first evening, plundered runs under the pale sky of the second afternoon.
Mullaney, one half of the key partnership in the historic win over Essex that booked Nottinghamshire's place at Lord's, completed the 12th first-class century of his career, punching the air as he might after a bout of nausea almost forced him to leave the field in the early part of his innings on Monday.
Once something of a bit-part player among stars at Trent Bridge, Mullaney has become a key figure in all formats. Always an all-round asset in the one-day sides, he has found his niche at the top of the order in the four-day side, and a useful partnership-breaking bowler to boot. Well respected in the dressing room, he led the side in Chris Read's absence last season and looks a natural choice to take on the captaincy in his own right when Read retires at the end of the season.
As a batsman, he may lack the flair and natural timing of Samit Patel, with whom he shared that epic stand at Chelmsford, and he does not dominate in the way Hales sometimes does. Yet he has the temperament to concentrate for long periods and packs a punch when the moment arrives to up the tempo.
He and Hales were together for 47.5 overs for the fourth wicket before Hales was caught on the rope attempting a second six straight off Joe Denly's leg spin, missing out by 15 on what appeared to be a certain hundred.
The innings lost some of its impetus after Hales. Riki Wessels was unusually subdued and Mullaney went an hour without scoring a boundary before a couple in quick succession off Adam Milne eased the pressure.
He passed his previous best, 166 against Somerset here last year, with a six off Will Gidman and the applause that accompanied his return to the pavilion, caught behind off Matt Coles, was a measure of his popularity. He acknowledged it properly, too, raising his bat to all corners of the ground.
Kent's bowlers have to be commended for the way they maintained their discipline and in denying Nottinghamshire their full complement of points they might consider they scored a minor triumph.
Yet, the possibly unwelcome consequence of this was that it was their batsman who were exposed to the day-into-night phase. After Bell-Drummond, Denly edged a fine, swinging ball from Fletcher to be caught behind before Harry Gurney struck twice, Sam Northeast following a ball outside off-stump to be caught behind, Sean Dickson edging to Brendan Taylor at third slip.
July 28, 11.36am - This story was updated with news of Ball's knee scan