Renteria: Rondon has 'consistent closer' potential

CHICAGO -- Hector Rondon has not had many save opportunities, but the Cubs right-hander does seem comfortable in his role as the closer and is progressing with an improved slider.

"Hector has the potential to be a closer, and a consistent closer," manager Rick Renteria said before the Cubs' 3-1 win on Thursday. "The last couple of days, all of us have noticed him using the slider a little more effectively and it's got more depth. He's been working on it.

"His slider earlier in the season was a little flatter and as hard as his fastball, and it was hard to distinguish," Renteria said.

Now, because the slider is better, Rondon's fastball is more effective, Renteria said.

Rondon was pressed into the role when Jose Veras struggled early this season. In his last 10 games, Rondon had given up two earned runs over nine innings for a 2.00 ERA. That's a big improvement over a nine-game stretch in June when he served up nine runs over 8 2/3 innings for a 9.35 ERA.

"As long as he maintains health and strength, he has the possibility of being a consistent closer," Renteria said.

With his save on Thursday -- his 14th -- Rondon has had 17 save opportunities this season, which is tied for 14th in the National League, far behind the leaders, Atlanta's Craig Kimbrel and St. Louis' Trevor Rosenthal, both with 36.