West Virginia coach Bob Huggins never doubted the status of the league's leading scorer.
Harris scored 22 points, Juwan Staten added 15 and the Mountaineers beat TCU 74-69 Saturday to improve to 3-0 against the Horned Frogs since both schools joined the league last season.
"He was going to play," Huggins said of Harris, who was 4 of 5 from 3-point range and hit one from long range that helped West Virginia (9-5) stay in front the entire second half even though TCU stayed close. "It's not anything major. It's just uncomfortable."
If Harris was uncomfortable coming off the bench for the first time this season because of the illness, it didn't show. Although he committed a turnover soon after entering the game, he hit his first 3 a couple of minutes later and finished the first half with 13 points.
"At the end of the day, I was going to try to play regardless," Harris said.
Amric Fields had a season-high 22 to the lead TCU (9-4) in his first Big 12 game. He missed most of the last season with a major knee injury that kept him out of the first three games this season. He recently returned from a four-game absence because of a broken left hand.
Brandon Parrish scored 18 points and had four 3-pointers, including one to get TCU within two with 3:06 remaining.
Kyan Anderson, TCU's leading scorer, finished with 12 points before fouling out with 6:26 remaining.
Staten hit back-to-back buckets to keep West Virginia in front in the final 3 minutes and made a breakaway layup to clinch the win in the waning seconds after TCU missed a pair of 3-pointers.
"We didn't really have a better option," Huggins said of Staten. "Eron got a little bit tired I think. We tried to throw it close as much as we could but that didn't help us much. He was Option 1 and 1A."
West Virginia built a lead early in the second half and stayed in front by dominating the offensive boards. The Mountaineers had three second-chance baskets in the first few minutes after halftime, with even the little guys getting involved.
Gary Browne, a 6-1 guard, missed a layup but tipped the ball in from the other side of the rim. With an eight-point lead down to two, the 6-3 Harris ended up with the ball for an easy layup and a 54-50 lead.
Terry Henderson had another put-back basket for a 65-60 lead as the Mountaineers had 17 offensive rebounds to eight for the Horned Frogs.
"We got beat all night long on the glass," Fields said. "We played well. They played well. We get a couple more rebounds here and there, then it's a different story I think."
TCU was in the double bonus for the last 8 minutes but missed several key free throws, including two by Hudson Price with the Horned Frogs down 65-62 with 4:26 remaining. Fields missed three straight in the second half, and the Frogs finished 10 of 17 at the line.
"I thought with the exception of some crucial free throws we missed, it was probably a pretty good basketball game," TCU coach Trent Johnson said. "I thought our guys were consistent in their effort in trying to execute the game plan."
Neither team led by more than five points in a high-scoring first half, with Fields matching Harris' 13 points before halftime.
TCU had the biggest lead at 28-23 after consecutive 3-pointers from Parrish.
West Virginia went ahead 36-35 when Staten found Harris for a long alley-oop dunk, and Nathan Adrian's 3-pointer with 1:12 left in the first half put the Mountaineers in front for good and gave them a 42-39 halftime lead.
Harris was 3 for 3 from 3-point range in the first half, although West Virginia shot just 39 percent as a team.
The Frogs were 7 of 10 from long range before halftime, with Fields, Parrish and Anderson each going 2 for 3.