Wednesday NBA: Heat (24-24) at Celtics (30-16)

The Miami Heat face their toughest three-game road stretch of the season beginning tonight in Boston (followed by visits to Cleveland and Chicago), and Miami may be very shorthanded against the Celtics.

Heat center Jermaine O’Neal (back spasms) did not practice Tuesday and is questionable . . . Forward Udonis Haslem (back spasms) did not practice but is probable. Starting point guard Mario Chalmers remains out at least another week with a partial tear in his left thumb. The Heat are 6.5-point betting underdogs on WagerWeb.com’s NBA odds.

The Heat have lost four in a row to Boston and 10 of 11. In the Heat’s 92-85 loss on Nov. 29, it allowed the Celtics to finish the game on a 14-3 run. In Miami’s 112-106 overtime loss on Jan. 6, Celtics guard Rajon Rondo converted a buzzer-beating alley-oop layup on an inbounds play to send the game into overtime.

But Boston will be without Paul Pierce tonight and is just 2-4 in its past six home games. Pierce suffered a strained left mid-foot injury during the first quarter of Boston’s 99-88 win at Washington on Monday. Pierce is officially day-to-day. Tony Allen would start for Pierce and give Boston a lineup that went 1-2 near the end of December while Pierce was out with knee problems. Allen had had 10 points and six rebounds in Monday’s win, filling in down the stretch with Pierce sidelined. Pierce is averaging 18.9 points, 4.7 rebounds and 3.4 assists.

Miami has lost four of five overall and is trying to hold on to the eighth and final playoff spot in the East. Miami plays eight of its next nine on the road, including seven against teams firmly in the playoff picture. A loss Wednesday would give the Heat its first losing record since it was 8-9 after a Nov. 29, 2008, loss to the Los Angeles Clippers. Miami guard Dwyane Wade is 1-for-11 on 3-pointers in the last two games.

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