Lee Tomlin: Injury worries mean forward was 'not fit to start' for Cardiff
Cardiff boss Neil Harris "does not know" how much the Bluebirds can rely on talisman Lee Tomlin as the forward continues to be troubled by injury.
Tomlin, 31, scored his eighth goal of the season to earn Cardiff a win over Derby that keeps the Bluebirds in the driving seat for a play-off spot.
However, it was the first time since the restart that Tomlin has been available to start a game for Cardiff.
"Lee has not been physically able to start games," said Harris.
"He's played an important part for us coming off the bench and in the dressing room as well.
"He's felt a lot better physically in the last few days and in a key moment, I thought it was important to get him back out on the pitch. Will he be available for Saturday? I don't know. I just don't know.
"He was excellent tonight and we hope we have him available on Saturday (at Middlesbrough) again."
Tomlin suffered a knee injury in training in February and Harris says he is still also dealing with issues with his hip.
However, when fit he is a key figure for Cardiff, as evidenced by them giving him a new contract in January.
The Cardiff boss says he would like to be able to use Tomlin more, with Cardiff currently in sixth in the Championship - two points clear of their play-off rivals with two games remaining.
"Maybe I've not made it clear Lee has not been physically able to start games. That's why he hasn't started, not because I've wanted to go with certain personnel," Harris added.
"Tonight was the first time he was at a level to contribute as he did and even playing him for 60, 70 minutes was a risk.
"We were not going to risk going past the drinks break with him whether we were winning, losing or drawing.
"Some days we can't get him out there because of the knee, sometimes the hip.
"I've wanted to play him at times and he's wanted to play, but he's not been in a position to start.
"But he's trained really well this week and we've pushed him. Is he available for Saturday? I won't know until at least Friday.
"We just have to manage him and take care of him."