In his outing on Monday in Durham, Howell allowed two runs on five hits.
Howell did not have a good ending to the first half, when he started against the Red Sox on July 5 at Fenway Park, and did not make it out of the first inning. He allowed six runs on six hits in two-thirds of an inning to take the loss in a 15-4 Red Sox win.
Rays manager Joe Maddon said they have not decided on who will start the afternoon game.
Jason Hammel is the most likely candidate to make the start, but right-hander Jae Kuk Ryu, who has been pitching in Durham, is also a possibility.
The essence of Upton: B.J. Upton moved into the No. 3 spot in the order on Tuesday night and the lineup had an upgraded look to it.
Since Upton returned to the lineup on Friday night, the Rays are batting .353 as a team (48-for-136), hiking the team mark from .261 to .265, its highest since June 27 (.265).
"[Upton] makes a big impact on the entire lineup and he allows us to do different things," Maddon said. "When one guy permits you to put other people in different spots that then augments you or makes you stronger in other ways.
"With [Ty Wigginton] hitting in the seventh and eighth hole right now, he's absolutely on fire. We've often talked about the American League lineup being able to score runs one through nine, and I think we're back at that point once again."
Wigginton entered Wednesday night's game looking to extend his hits streak from a team-tying eight in a row. Maddon said Wigginton has been more selective lately, but he added another reason for Wiggy's success: "I think I've seen him sneaking some Snickers bars."
Snickers bars are taboo in the mandated health-food atmosphere inside the Rays' clubhouse.
The Major League record for hits in consecutive plate appearances is 12, a record shared by Mike Higgins (Boston, 1938) and Walt Dropo (Detroit, 1952).
Day game after a night game: The lineup for Thursday afternoon's game will likely have a different look given the fact it's a day game following a night game. Maddon has already said that Brendan Harris will not start, noting that they have ridden Harris pretty hard and he wants to try and facilitate his shortstop's continued success for the remainder of the season. Upton, who is playing well but is coming off a stint on the disabled list with a strained left quadriceps, is also a candidate to sit out Thursday afternoon's contest.
Aki struggles: Akinori Iwamura is in the midst of a minor slump. Since the All-Star break, Iwamura is hitting just .167 (4-for-24) and has hit .258 (42-for-163) in 39 games since returning from a 29-day stint on the DL recovering from a right oblique strain. In addition, Iwamura became a first-time father over the break.
Maddon didn't seem too concerned about his third baseman's lack of hitting lately, noting that Iwamura is the kind of player who can help a team win with his legs and his glove when he's not hitting. He added: "Anytime you have a baby in the middle of the season, it messes you up."
Inside the Rays' Minor Leagues: FSN Florida traveled to Montgomery, Ala., and Vero Beach, Fla., to check out some of the Rays' top prospects at Class A Vero Beach and Double-A Montgomery for the upcoming new edition of Inside the Rays: Minor Leagues, which premieres on Saturday at noon ET and will have multiple encores.
Montgomery's Reid Brignac and Evan Longoria, who play shortstop and third base, respectively, will be featured prominently as will the Vero Beach Rays, who play in Holman Stadium, which is part of what is better known as Dodgertown. Since 1948, the Los Angeles Dodgers have called Vero Beach their Spring Training home. The show will take a peek at top prospects, this edition will focus on pitchers Wade Davis and Jake McGee, who appreciate the history and mystique of their surroundings.
Up next: The Rays finish their three-game series against the Angels on Thursday afternoon in a 12:10 p.m. ET contest at Tropicana Field. Right-hander Andy Sonnanstine will start for the Rays and will be opposed by right-hander Kelvim Escobar.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.